This easy peanut butter mug cake is fudgy, moist, made in the microwave, and ready in under 5 minutes. Add chocolate chips or an extra drizzle of peanut butter on top for an irresistible single-serve dessert.
When time is short and you want something sweet, this peanut butter mug cake delivers. It sits somewhere between a peanut butter cookie and a fudgy cake: tender, moist, and with a rich peanut butter flavor that isn’t overly sweet.
I first shared a vanilla mug cake recipe recently and the response was incredible. After the vanilla and chocolate versions, I couldn’t resist creating a peanut butter version — soft, fudgy, and ready in moments.
How to Make a Peanut Butter Mug Cake 
Mug cakes are popular because they’re quick, require just a few ingredients, and are cooked in the microwave. For this peanut butter mug cake you’ll need:
- 1 1/2 tablespoons oil
- 2 tablespoons peanut butter
- 2 tablespoons sugar
- 1 large egg yolk (or 1 extra tablespoon milk for an egg-free option)
- 2 tablespoons flour
- 1/4 teaspoon baking powder
- 2 tablespoons milk
- Optional: 1 tablespoon chocolate chips
To assemble: add the oil, peanut butter, sugar, and egg yolk to a large mug and whisk until smooth. Stir in the flour and baking powder, then whisk in the milk. Fold in chocolate chips if you like. Microwave for about 1 minute 30 seconds, or until the top puffs and looks set. Let the cake rest for 1–2 minutes before topping — a scoop of ice cream or a drizzle of peanut butter is perfect.
Egg-free variation
To make this without an egg, replace the yolk with 1 extra tablespoon of milk. The egg yolk gives a slightly extra moist, fudgy texture, but using milk works well too.
Chocolate peanut butter version
To make a chocolate peanut butter mug cake, add 2 teaspoons of cocoa powder along with the flour. This gives a deeper chocolate flavor while keeping the peanut butter character.
This mug cake is ideal for late-night cravings or when you want a warm, comforting dessert without making a full batch. It’s quick, satisfying, and has a great, balanced peanut butter flavor.
For more single-serve mug cake ideas, try vanilla or chocolate mug cakes. For other easy peanut butter treats, explore simple cookie and no-bake recipes.
Peanut Butter Mug Cake
Fiona Dowling
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1 mug cake
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Ingredients
- 1 1/2 tablespoons oil
- 2 tablespoons peanut butter
- 2 tablespoons sugar
- 1 large egg yolk, or 1 extra tablespoon milk
- 2 tablespoons flour
- 1/4 teaspoon baking powder
- 2 tablespoons milk
- 1 tablespoon chocolate chips (optional)
Instructions
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Add the oil, peanut butter, sugar, and egg yolk to a large mug. Whisk until smooth.
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Whisk in the flour and baking powder.
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Stir in the milk and optional chocolate chips.
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Microwave for 1 minute and 30 seconds, or until the top looks set.
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Let stand 1–2 minutes to cool slightly, then top with ice cream or a drizzle of peanut butter.
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