5-Minute Banana Mug Cake

A warm, single-serve banana cake that you mix and cook right in a mug. It uses a ripe banana for moisture and real flavor, and it’s done in the time it takes to preheat an oven.

The inside stays soft and tender, not gummy, and the top sets just enough to hold a spoonful of whipped cream. It’s the dessert you make when you want something sweet without baking an entire cake.

Why This Mug Cake Works

One ripe banana carries a lot of the work here. Its natural sweetness means you can use less added sugar, and the soft texture it gives the batter keeps the cake from drying out in the microwave.

Because everything measures in spoonfuls and cooks in one cup, cleanup is a fast rinse. I reach for it on nights when a proper dessert sounds nice but no one wants to wait.

Ingredients

• 1 small ripe banana (about 4 oz): the riper the better, with plenty of brown spots for sweetness and moisture.
• 1 large egg: room temperature blends in more smoothly.
• 1 tbsp unsalted butter, melted and slightly cooled: adds richness; substitute with neutral oil if needed.
• 3 tbsp all-purpose flour: spooned and leveled, not scooped, so the cake stays light.
• 1 tbsp granulated sugar: sweetens just enough; you can use coconut sugar or maple syrup.
• ¼ tsp baking powder: the leavening that gives the cake a soft rise.
• ¼ tsp vanilla extract: for that warm baked-goods aroma.
• Pinch of salt: sharpens the banana flavor.
• 2 tbsp semisweet chocolate chips: (optional): fold in at the end for melty pockets.

Variations / Substitutions

• Swap the sugar: maple syrup or honey work, use 1 tbsp and reduce the butter by a teaspoon to balance moisture.
• Add spice: a pinch of cinnamon or a scrape of nutmeg makes it cozy.
• Use a flax egg: mix 1 tbsp ground flax with 2 tbsp water and let it sit 5 minutes; the cake will be a little denser but still good.
• Make it dairy free: use melted coconut oil or a neutral oil instead of butter.

Moist Banana Cake is another reader favorite dessert worth making next.

How To Make Banana Mug Cake

Step 1: Mash the Banana

Choose a microwave-safe mug that holds at least 12 oz, so the cake has room to puff up. Peel the banana, drop it into the mug, and mash it with a fork until you have a fairly smooth paste, about 30 seconds of mashing. A few tiny lumps are fine.

Step 2: Stir in the Wet Ingredients

Crack the egg right into the mashed banana, then add the melted butter and vanilla extract. Switch to a fork or a small whisk and stir until the mixture looks uniform and glossy, about 20 seconds of mixing. No streaks of egg white should remain.

Step 3: Fold in the Dry Ingredients

Sprinkle the flour, sugar, baking powder, and salt over the wet mixture. Using a fork, gently fold and stir just until no dry pockets are visible. A light hand matters here — about 15 strokes total is plenty. If you’re using chocolate chips, fold them in now with a couple of stirs.

Step 4: Microwave the Batter

Place the mug in the center of the microwave and cook on high power for 1 minute. Start with 1 minute, then check. The top should look dry and set while the center is still slightly glossy and soft to the touch. If it looks wet, add 10-second bursts until done. A standard 900W microwave takes 1 minute; higher or lower wattages need a slight adjustment.

Step 5: Top and Dig In

Let the mug sit on the counter for 1 minute — it will continue setting up as it cools. Spoon a dollop of whipped cream, a handful of extra chocolate chips, or a drizzle of honey right on top, grab a spoon, and eat it while it’s still warm.

Tips for the Fluffiest Mug Cake

• Start with a really ripe banana. One with dark spots and soft flesh gives the batter more moisture and a sweeter base, so you don’t miss the extra sugar.
• A fork works fine, but if you have a small whisk, use it for the wet mix. It reduces lumps and helps you avoid overmixing the flour later.
• Stop stirring the moment the flour disappears. Overworked batter makes a tough, rubbery cake.
• A 12-ounce mug is the sweet spot. Smaller mugs risk spillover; much larger ones spread the batter thin and dry it out.

Microwave times vary by wattage. Use these as a starting point.

Frequently Asked Questions

Can I use a flax egg to keep it vegan?

Yes, a flax egg works, but the cake will be a bit more dense and the rise will be lower. Use 1 tbsp ground flaxseed mixed with 2 tbsp water, let it thicken 5 minutes, and add it where the egg is listed.

My mug cake overflowed and made a mess. What went wrong?

Your mug might be too small. Switch to one that holds at least 12 ounces, and fill it only about two-thirds of the way with batter to leave room for the cake to puff up.

Can I make this gluten free?

You can. Replace the all-purpose flour with an equal amount of a 1-to-1 gluten-free flour blend. The texture will be close, though the top may brown a little less.

Why did my cake turn out spongy and chewy?

Mixing the batter too long develops the gluten in the flour, which gives a chewy texture. Fold the dry ingredients in gently and stop as soon as the flour is absorbed.

Banana Mug Cake Recipe

Print Recipe Pin Recipe

Prep Time 3 minutes mins

Cook Time 1 minute min

Total Time 4 minutes mins

Servings: 1 servings

Calories: 412

Ingredients Method Notes

Ingredients

  

• 1 small ripe banana (about 4 oz)
• 1 large egg
• 1 tbsp unsalted butter, melted and slightly cooled
• 3 tbsp all-purpose flour
• 1 tbsp granulated sugar
• ¼ tsp baking powder
• ¼ tsp vanilla extract
• Pinch of salt
• 2 tbsp semisweet chocolate chips (optional)

Method

 

1. Place the banana in a 12-ounce microwave-safe mug and mash until smooth with a fork.
2. Add the egg, melted butter, and vanilla, and stir until fully combined.
3. Sprinkle in the flour, sugar, baking powder, and salt, and gently fold just until no dry streaks remain. Fold in chocolate chips if using.
4. Microwave on high for 1 minute (adjust for wattage), until the top is set but the center is slightly glossy.
5. Let it rest 1 minute, then top with whipped cream or extra chocolate chips and enjoy warm.

Notes

The cake tastes best right after it cools for a minute, when it’s still soft and steamy. If you want a drier, more bread-like texture, microwave for an additional 10 to 15 seconds, but keep an eye on it so it does not dry out.