Classic
Banana Mug Cake
Ripe banana sweetness, soft crumb, and a cozy banana-bread feel without an egg.
Steps
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Mash banana directly in a 12 oz microwave-safe mug until mostly smooth with a few small soft pieces left.
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Stir in flour, brown sugar, baking powder, cinnamon, and salt until the banana is coated and no dry pockets remain.
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Add milk and oil. Mix just until the batter loosens; overmixing mashed banana can make the cake gummy.
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Fold in walnuts if using, keeping a few on top for texture.
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Microwave 65-75 seconds, then rest two minutes. The center should be soft, not wet.
Helpful notes
The banana should be ripe and speckled. If it is very large or watery, measure the mashed banana instead of adding the whole fruit.
Source note
Source-checked against banana mug cake and banana bread mug cake patterns using mashed ripe banana, a small amount of leavener, and brief microwave cooking; adapted eggless with measured milk to avoid gumminess.
Success guide
Make it work the first time
Expected texture
Expect a cozy, steamed-cake texture rather than oven-browned edges. Pull it when the surface is set and let the mug finish the job while it rests.
Success tips
- Use a microwave-safe mug with visible headroom. If the batter fills more than about half the mug, move it to a larger mug before cooking.
- Start with the lower end of the microwave time in the steps. Add time in short bursts only if the center still looks wet.
- Let the cake rest before eating. The crumb keeps setting after the microwave stops, and the mug will be very hot.
- This recipe avoids a whole egg, which helps prevent the bouncy texture people often dislike in small mug cakes.
Substitutions
- Milk
- Whole milk gives the softest crumb. Unsweetened oat or almond milk can work, but the cake may taste a little lighter.
- Fat
- Neutral oil keeps mug cakes moist. Melted butter works in some chocolate or vanilla cakes, but it can make the crumb firmer as it cools.
- Flour
- Do not assume a direct gluten-free flour swap unless the blend is labeled cup-for-cup; the texture may turn gummy.
Troubleshooting
- Rubbery texture
- Usually caused by overmixing, overcooking, or too much egg for one mug. Mix only until no dry flour remains and stop at the first set-top cue.
- Dry crumb
- The cake likely cooked too long. Next time start at the low end of the time range and let rest instead of microwaving until fully dry.
- Overflow
- The mug was too small or too full. Use more headroom and set the mug on a paper towel if your microwave runs hot.
- Wet center
- Microwave in one short burst, then rest again. A slightly glossy center is fine; a puddle of batter needs more time.
Variations
- Add a tiny pinch of cinnamon or nutmeg to make the cake taste warmer.
- Serve with a scoop of ice cream if you want a hot-and-cold dessert.
