Moist Banana Bread Mug Cake (No Egg & Never Rubbery)

Why you’ll love this banana mug cake

You know that one lonely brown banana on the counter that no one wants to touch? This is what it’s been waiting for. In about 5 minutes you go from “I should probably throw that out” to a warm, cozy banana bread situation you can eat straight from the mug. No sharing required.

Most mug cakes taste fine for the first two bites, then turn weirdly rubbery or dry. This one doesn’t. There’s no egg in the batter, so you don’t get that bouncy, scrambled-egg texture that happens in the microwave. The mashed banana does the binding instead, giving you a soft, cake-meets-banana-bread crumb that actually stays moist as it cools. Total game changer.

Everything mixes right in the mug with a fork. No mixer. No bowls. I usually throw it together while my kid is brushing teeth and it’s ready before she’s picked a bedtime story. You’ll use simple pantry ingredients: flour, brown sugar, melted butter, baking powder, milk, cinnamon, and a good pinch of salt to keep it from tasting too sweet. That’s it.

And the timing is wattage-smart. I walk you through what to do whether your microwave is a tiny dorm model or a powerful newer one, so you don’t accidentally cook your cute little cake into a hockey puck. The top comes out set and fluffy with a slightly gooey center, just like the middle slice of banana bread.

From there, you can dress it up however you want. Sprinkle in chocolate chips, swirl in peanut butter or Nutella, or keep it simple with a little cinnamon sugar on top. Late-night treat. After-school snack. “I deserve cake” moment on a Tuesday. This cozy banana bread in a mug’s ready whenever you are.

Craving more cozy single-serve desserts? Head over to The Ultimate Guide to Mug Cakes for flavor ideas, timing tricks, and troubleshooting all in one place.

Ingredients & substitutions

You only need a handful of pantry staples for this cozy banana mug cake. Nothing fancy. Nothing weird.

Here’s what I use most often:

• 1 small overripe banana (or ½ large), well mashed – about ⅓ to ½ cup
• 1 tablespoon unsalted butter, melted
• 1 to 2 tablespoons brown sugar, packed
• 1 tablespoon milk (dairy or non-dairy)
• ¼ teaspoon vanilla extract
• ⅛ teaspoon ground cinnamon
• 3 to 4 tablespoons all-purpose flour
• ½ teaspoon baking powder
• A generous pinch of salt
• 1 tablespoon chocolate chips or chopped nuts (optional, but highly encouraged)

Let’s break it down.

The banana

The riper the banana, the better. Lots of brown spots. Almost too far gone. That’s where the sweetness and moisture come from. If your banana is on the firmer side, use the full 2 tablespoons of sugar. Very sweet banana? You can get away with 1 tablespoon.

Aim for at least ⅓ cup mashed banana so the cake stays moist and fudgy, not dry. I’ll sometimes scrape the last bits off the peel with a spoon to make sure I have enough. Works every time.

Fat and liquid

Melted butter gives that buttery banana bread flavor and a richer crumb. You can swap in vegetable oil, canola oil, or melted coconut oil if you prefer or want it dairy-free. Use the same 1 tablespoon.

For the liquid, any milk works: whole, 2%, almond, oat, soy. Just stick to 1 tablespoon so the batter isn’t soupy. And if you’re using salted butter, you can slightly reduce the pinch of salt. But don’t skip it entirely.

Sweetener and flavor

Brown sugar adds moisture and a light caramel note that makes this taste like bakery-style banana bread in a mug. You can use white sugar in a pinch, but the flavor will be a little flatter, so add an extra tiny splash of vanilla. Coconut sugar also works.

Cinnamon is optional but cozy. Vanilla is non-negotiable for me. Tiny amount, big difference.

Dry ingredients

All-purpose flour keeps things soft and tender. Start with 3 tablespoons, then add up to 1 extra tablespoon if your batter looks very runny (super juicy bananas usually need the extra). The batter should be thick but scoopable, like muffin batter.

Baking powder is what makes the cake rise quickly in the microwave. Make sure it’s fresh. If it’s older than a year, grab a new tin. Old baking powder = sad, dense cake.

Easy swaps: vegan, dairy-free, gluten-free

• Vegan / Dairy-free: Use oil or melted dairy-free butter and plant milk. The base is already egg-free.
• Gluten-free: Swap in a 1:1 gluten-free all-purpose blend. Make sure it’s labeled cup-for-cup.
• Nut-free: Skip the nuts and use dairy-free chocolate chips if needed.

And of course, mix-ins are where you make it your own. A spoonful of chocolate chips, a sprinkle of chopped walnuts, or a tiny dollop of peanut butter on top turns a simple mug cake into something you’ll “accidentally” make twice in one night.

Choosing the right mug (important!)

I know, it’s “just a mug,” but this little choice can totally make or break your banana mug cake. Wrong mug = overflow volcano or weirdly undercooked middle. Not fun.

Size

Aim for a 10 to 12 ounce mug. Bigger is fine, smaller is not. You want the batter to fill the mug about halfway before cooking. That leaves room for the cake to rise without spilling over the sides.

If your favorite mug is on the smaller side, you can still use it, just hold back a spoonful or two of batter and microwave the rest. Instant snack for later.

Shape & material

Straight-sided mugs or short, wide mugs cook more evenly than tall, skinny ones. In a very tall mug, the bottom can overcook before the top is set.

Use a microwave-safe ceramic mug or ramekin. Avoid anything metal (obviously) and be cautious with very thin glass, which can get scorching hot. If your mug has a gold rim or metallic design, skip it for this recipe.

Quick mug test

Not sure if your mug is microwave-safe or how hot it gets? Fill it halfway with water and microwave for 1 minute. The water should be hot, but the handle shouldn’t feel like lava. If it does, grab a different mug for cake time.

And one last note: even in the right mug, this cake rises fast. If you’re worried about overflow, set the mug on a small plate before microwaving. Easy insurance and no surprise mess in the microwave.

Step-by-step: how to make banana mug cake

This all happens right in the mug, so pull it out first and grab a fork. That’s your main tool.

1. Mash the banana

Peel your very ripe banana and pop about ½ of it (or 1 small one) into the mug. Mash it with the fork until mostly smooth with just a few small lumps. You should have roughly ⅓ to ½ cup.

If you prefer, mash in a small bowl and scrape it into the mug. Slightly extra dishes, but easier if your mug has narrow sides.

2. Stir in the wet ingredients

To the mashed banana, add:

• 1 tablespoon melted butter
• 1 to 2 tablespoons brown sugar
• 1 tablespoon milk
• ¼ teaspoon vanilla

Whisk everything together with the fork until it looks glossy and evenly combined. No big streaks of butter or sugar. Smell that? Already good.

3. Add the dry ingredients

Sprinkle in:

• 3 tablespoons flour
• ½ teaspoon baking powder
• ⅛ teaspoon cinnamon
• Pinch of salt

Use the fork to gently stir just until you don’t see dry flour. Scrape along the bottom and sides so nothing hides there. The batter should be thick and scoopable, not runny. If it’s very thin (super juicy banana!), stir in up to 1 extra tablespoon flour.

And stop mixing as soon as it comes together. Overmixing = more gluten = tougher cake.

4. Fold in mix-ins

If you’re adding chocolate chips, nuts, or a peanut butter/Nutella swirl, fold those in now. Keep a few chips on top if you want a prettier finish. Totally optional, but fun.

5. Microwave in short bursts

Place the mug in the microwave (on a small plate if you’re nervous about overflow).

• 1000W microwave: Start with 60 seconds.
• 1200W microwave: Start with 45–50 seconds.
• 700–800W microwave: You’ll likely need 70–80 seconds.

After the first round, check it. The top should look mostly set around the edges with a slightly shiny, soft center. If it still looks very wet or soupy, microwave in 10–15 second bursts, checking after each one.

Remember, it will keep cooking from residual heat, so stop when the center is just barely glossy and springs back lightly when tapped. If you wait until it’s totally dry on top, it’ll be overdone underneath.

6. Let it rest

This part is important. Carefully remove the mug (the handle might be hot) and let the cake sit for 1 to 2 minutes.

The crumb finishes setting during this minute, and the texture shifts from “pudding-ish” to soft banana bread. Plus, your tongue will thank you.

No microwave?

Spoon the batter into a lightly greased 6–8 ounce ramekin and bake at 350°F for about 18–22 minutes, until the top is set and a toothpick comes out with a few moist crumbs. Same cozy banana cake, just oven-baked.

Troubleshooting: avoiding a rubbery mug cake

If you’ve ever dug into a mug cake and felt like you were chewing on a sponge, you’re not alone. Mug cakes are tiny, so they go from perfect to overcooked very fast. The good news: once you know what causes that rubbery texture, it’s easy to avoid.

Problem: My mug cake is rubbery or tough

The usual culprits are overmixing and overcooking. When you stir flour too much, you develop more gluten, which makes the cake chewy instead of tender. Then the microwave blasts it with heat and it tightens up even more.

Fix it: Stir the dry ingredients in just until the flour disappears. A few tiny lumps are totally fine. Then cook in short bursts and stop as soon as the top looks mostly set with a slightly soft center.

Problem: The top looks wet, so I kept cooking it

In the microwave, the center always looks a little shinier than the edges. That’s normal. If you cook until the entire top is totally dry, the inside will be overdone. And by the time it cools, it’s hockey puck territory.

Fix it: Stop when the center is just barely glossy and springs back lightly when tapped with a fingertip. Then let it sit for a full minute. Carryover heat finishes the job without drying it out.

Problem: It’s dry and crumbly

This usually means there wasn’t quite enough banana or fat, or it was microwaved a bit too long for your mug size and wattage.

Fix it next time by:

• Making sure you have at least ⅓ cup mashed banana
• Using the full tablespoon of butter or oil
• Shaving 10–15 seconds off the cook time

If it’s already dry, you can rescue it with a drizzle of milk or a tiny splash of cream over the top while it’s still warm. Instant “banana bread pudding” vibes.

Problem: It overflowed everywhere

Too small mug or too full. It happens.

Fill your mug only about halfway next time and set it on a plate before microwaving. Same fluffy cake, no microwave cleanup.

4 delicious variations

Once you’ve got the base banana mug cake down, it’s basically a playground. Same batter, tiny tweaks, totally different mood.

1. “Monkey Bread” cinnamon-sugar swirl

For when you want banana bread and cinnamon rolls at the same time. Dangerous combo.

• Make the base batter as written.
• In a small bowl, stir together 1 teaspoon brown sugar and ¼ teaspoon cinnamon.
• Spoon half the batter into the mug.
• Sprinkle most of the cinnamon sugar over it, then add the rest of the batter.
• Swirl gently with a butter knife or toothpick. Don’t overmix.
• Sprinkle the last bit of cinnamon sugar on top and microwave as directed.

You’ll get those melty pockets of cinnamon sugar that taste like mini monkey bread bites in the middle of your cake.

2. Chocolate lover (or double chocolate)

Think banana bread meets brownie.

• Add 1 to 2 teaspoons unsweetened cocoa powder with the dry ingredients.
• If you add cocoa, start with the full 2 tablespoons brown sugar so it doesn’t taste bitter.
• Fold in 1 tablespoon chocolate chips and save a few for the top.

Microwave as usual. The top should look shiny and a little fudgy, more like a brownie than a plain cake. Very good with a scoop of vanilla ice cream if you’re going all in.

3. Nutty Professor peanut butter swirl

This one is pure comfort. Salty-sweet, a little messy, totally worth it.

• Make the base batter and pour it into the mug.
• Warm 1 tablespoon peanut butter in the microwave for about 5–10 seconds until it’s runny.
• Drizzle it over the batter and use a knife or skewer to swirl it through.
• If you like crunch, sprinkle a teaspoon of chopped walnuts or peanuts on top.

Microwave as directed. You’ll get pockets of warm, melty peanut butter in every few bites.

4. Simple vegan banana mug cake

Already egg-free, so this is easy. No weird substitutions.

• Use 1 tablespoon neutral oil or melted vegan butter instead of regular butter.
• Use almond, oat, soy, or coconut milk instead of dairy milk.
• Double-check your chocolate chips are dairy-free if you’re adding them.

Everything else stays the same: same banana, same flour, same baking powder. Same fluffy, cozy cake in a mug, just plant-based.

Banana Mug Cake Printable Recipe Card

2-Minute Moist Banana Mug Cake (No Egg)

Yield: 1 mug cake

Prep Time: 3 minutes

Cook Time: 1 minute

Additional Time: 1 minute

Total Time: 5 minutes

A cozy banana bread mug cake that bakes right in your microwave in about a minute. No egg, no rubbery texture, and easy vegan or gluten-free swaps.

Print

Ingredients

• 1 small overripe banana (or 1/2 large), mashed well (about 1/3 to 1/2 cup)
• 1 tablespoon unsalted butter, melted (or neutral oil for dairy-free)
• 1 to 2 tablespoons packed brown sugar (to taste, depending on banana sweetness)
• 1 tablespoon milk (dairy or plant-based)
• 1/4 teaspoon vanilla extract
• 1/8 teaspoon ground cinnamon
• 3 tablespoons all-purpose flour (add up to 1 extra tablespoon if batter is very runny)
• 1/2 teaspoon baking powder
• A generous pinch of salt
• 1 tablespoon chocolate chips or chopped nuts (optional)

Instructions

1. Choose a microwave-safe mug that holds at least 10 to 12 ounces so there is room for the cake to rise without overflowing.
2. Peel the banana and add about 1 small banana (or 1/2 large) to the mug; mash very well with a fork until mostly smooth with just a few small lumps.
3. Add the melted butter, brown sugar, milk, and vanilla to the mashed banana and whisk together with the fork until the mixture looks smooth and glossy.
4. Sprinkle the flour, baking powder, cinnamon, and salt evenly over the wet mixture, then gently stir with the fork just until you no longer see dry flour.
5. Check the batter consistency; it should be thick but scoopable like muffin batter, not soupy; if it seems very runny, stir in up to 1 extra tablespoon flour.
6. Fold in the chocolate chips or nuts, if using, and smooth the top of the batter in the mug; add a few extra chips on top for looks if you like.
7. Place the mug in the microwave (on a small plate if you are worried about overflow).
8. For a 1000W microwave, cook on high for about 60 seconds; for a 1200W microwave, start with 45 to 50 seconds; for a 700 to 800W microwave, start with 70 to 80 seconds.
9. Open the microwave and check the top; the edges should look set and the center should look just slightly glossy but not liquid.
10. If the batter still looks very wet or soupy in the center, continue microwaving in 10 to 15 second bursts, checking after each burst so you do not overcook it.
11. Stop cooking when the cake springs back lightly when tapped in the center; it will continue to firm up from residual heat as it cools.
12. Carefully remove the mug using an oven mitt if needed and let the cake rest for 1 to 2 minutes before eating so the crumb can finish setting and the mug can cool slightly.
13. Serve warm straight from the mug with extra chocolate chips, a scoop of ice cream, or whipped cream if desired.

Notes

• hoose a microwave-safe mug that holds at least 10 to 12 ounces so there is room for the cake to rise without overflowing.
• Peel the banana and add about 1 small banana (or 1/2 large) to the mug; mash very well with a fork until mostly smooth with just a few small lumps.
• Add the melted butter, brown sugar, milk, and vanilla to the mashed banana and whisk together with the fork until the mixture looks smooth and glossy.
• Sprinkle the flour, baking powder, cinnamon, and salt evenly over the wet mixture, then gently stir with the fork just until you no longer see dry flour.
• Check the batter consistency; it should be thick but scoopable like muffin batter, not soupy; if it seems very runny, stir in up to 1 extra tablespoon flour.
• Fold in the chocolate chips or nuts, if using, and smooth the top of the batter in the mug; add a few extra chips on top for looks if you like.
• Place the mug in the microwave (on a small plate if you are worried about overflow).
• For a 1000W microwave, cook on high for about 60 seconds; for a 1200W microwave, start with 45 to 50 seconds; for a 700 to 800W microwave, start with 70 to 80 seconds and then add more time in 10 to 15 second bursts as needed.

Nutrition Information:

Yield: 1 Serving Size: 1 Mug
Amount Per Serving: Calories: 420Total Fat: 18gSaturated Fat: 10gCarbohydrates: 60gSugar: 32gProtein: 5g

Nutrition values are estimates and will vary based on ingredients and brands.

Banana mug cake FAQ

Let’s hit the most common banana mug cake questions so you feel totally confident before you mash that banana.

More fun single-serve cakes to try

Once you’ve made this banana mug cake a couple of times, it’s very hard not to want “just one more” something-sweet. Good news: you’ve basically unlocked a whole little universe of single-serve cakes.

Here are a few fun ideas to link to or keep in your back pocket for later:

• 3-Ingredient Banana Mug Cake
  For those “I have 90 seconds and zero brain cells left” nights. This one usually leans more “healthy-ish” and snacky than full-on dessert, so it’s a nice contrast to this richer, bakery-style version.
• Classic Chocolate Mug Cake
  Same cozy, microwave-fast idea, but pure chocolate. Great for people who don’t love banana or when your bananas are annoyingly still green. Think soft, fudgy middle you can top with ice cream or a dollop of whipped cream.
• Peanut Butter Chocolate Chip Mug Cake
  All the salty-sweet vibes, no mixer. This one’s basically a warm cookie in a mug, loaded with melty chocolate chips. Very dangerous in the best way.
• Cinnamon Roll Mug Cake
  A fluffy vanilla-cinnamon base with a quick swirl of brown sugar and cinnamon, finished with a simple powdered sugar glaze. Weekend brunch energy, but you can totally eat it in sweats on the couch.

You can cross-link these right in the post so readers who fall in love with this banana version have a clear “next cake” to try. One banana today, a chocolate mug cake tomorrow. Totally reasonable.

Love This Recipe? Discover More Mug Cake Favorites

If this mug cake hit the spot, don’t miss The Ultimate Guide to Mug Cakes. Inside you’ll find small-batch classics, over-the-top flavor combos, and quick fixes for every rubbery or overflowed mug moment. From brownie-style chocolate to bright lemon and gooey cookie dough, there’s a microwave treat for every craving.