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Bring cozy comfort straight to your mug with this 5-minute Peanut Butter Mug Cake, warm, fluffy, and packed with peanut butter flavor. You can make it in the microwave using just a handful of pantry staples. It’s the perfect single-serve dessert for late-night cravings or movie marathons.
If you love single-serve desserts, try my 1-Minute Brownie Mug Cake or Protein Chocolate Chip Cookie in a mug, or browse around my 14 Single Serve Desserts Made In The Microwave to find your go to weeknight dessert!
Omgosh this was the best! We’ve tried a few mug recipes before, and typically they are mediocre leaving me craving a real dessert. This was incredible and totally took care of my sweet tooth!! We topped it with ice cream 🙂
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There’s something so nostalgic about this recipe, it’s something I used to make all throughout college. When I first tested this mug cake, I couldn’t believe how soft and moist it turned out in just a minute. It’s the ideal “self-care” treat for nights when you want something sweet fast, with no oven required.
The best part? It’s completely customizable. Add chocolate chips, a drizzle of Nutella, or even a scoop of ice cream, because mug cakes are meant to make life easier and more indulgent.
Why You’ll Love This Peanut Butter Mug Cake
This isn’t your average mug cake. It’s warm, gooey, and ready in under five minutes, the kind of dessert that feels indulgent without any effort. Here’s why this recipe is special:
- Microwave magic: No oven, no waiting! It cooks in just 60 seconds.
- Soft and moist every time: Thanks to the peanut butter and brown sugar combo.
- Minimal cleanup: You only need one mug and a spoon.
- Totally customizable: Add chocolate chips, drizzle caramel, or swirl in more peanut butter, make it yours.
Ingredients for the Best Peanut Butter Mug Cake
You only need a few pantry staples to make this soft, gooey 5-minute peanut butter mug cake:
- Butter: Adds richness and moisture. I use salted butter for extra flavor.
- Peanut butter: The star ingredient! Use creamy peanut butter, I love Skippy or Jif for a perfectly balanced texture.
- Egg yolk: Keeps the cake tender and rich without drying out.
- Brown sugar: Sweetens the cake while adding a caramel-like depth that pairs perfectly with peanut butter.
- Milk: Helps create that light, fluffy crumb. Any milk works (dairy or plant-based).
- Flour: All-purpose flour gives the right structure for a soft but stable mug cake.
- Baking powder: Gives the cake its gentle rise in the microwave.
- Vanilla extract (optional): Adds a cozy, bakery-style aroma.
- Toppings (optional): I love adding a spoonful of vanilla frosting and a sprinkle of crushed peanuts for extra indulgence.
Substitutions
- No egg yolk? Replace with 1 tbsp unsweetened applesauce or a flax-egg.
- Gluten-free option: Use 1:1 gluten-free flour blend.
- Dairy-free: Use oil instead of butter and oat or almond milk.
Add-Ins & Variations
- Chocolate Peanut Butter Mug Cake: Add 1 tsp cocoa powder and 1 tbsp chocolate chips.
- Molten Center: Place a Lindt truffle or chocolate square in the center before microwaving. I actually use this hack in my Oreo mug cake and it turns out DELICIOUS!
- Double Peanut Butter: Swirl in peanut butter chips or drizzle extra on top after cooking.
How to make peanut butter mug cake Step-By-Step
- Start by melting the butter in the mug, Add the peanut butter, and stir until combined. Add in the egg yolk, the brown sugar, and the milk and stir again.
- Add the flour and the baking powder and stir one last time until it’s completely smooth.
- Cook in the microwave on high for 60 seconds. Top it with vanilla frosting and crushed peanuts or enjoy on it’s own.
Serving suggestion – Serve it warm with vanilla ice cream, a drizzle of chocolate sauce, or a sprinkle of flaky salt for the ultimate sweet-salty combo.
Expert Tips to Make this Peanut Butter Mug Cake
- Microwave power matters: Higher wattage will require less time to bake.
- Don’t overcook! Start with 50–55 seconds and add time in 10-second bursts as needed.
- Use a medium mug (10–12 oz) to avoid overflow.
- Add mix-ins like chocolate chips, crushed cookies, or a Reese’s cup for variety.
Troubleshooting
- Cake came out dry? Microwave time was too long, reduce by 5–10 seconds next time.
- Rubbery texture? Batter was overmixed. Stir until just combined.
- Cake overflowed? Use a larger mugThis usually happens when your mug is too small or your microwave runs hot. Try filling your mug only halfway and cooking in shorter bursts. You can also read this helpful guide from Epicurious on improving mug cakes for more troubleshooting tricks.
Frequently Asked Questions -FAQs
Whether you’re craving something warm after dinner or need a quick pick-me-up, this peanut butter mug cake hits every craving without the wait.
Because this is a single-serve cake, leftovers are rare. If you do refrigerate it, store covered and consume within 24 hours. To prep ahead, mix the dry ingredients only, store in a jar, and add wet ingredients when ready.
Yes, mix the batter, pour into a freezer-safe mug, flash-freeze, then seal. When ready, microwave for about 70 seconds (instead of 60) for a fresh-baked feel.
Absolutely. Replace the egg yolk with 1 tablespoon unsweetened applesauce or a flax-egg (1 tsp ground flax + 2 tbsp water). Swap butter with coconut oil and use plant-based milk.
I love using chocolate chips, peanut butter cups, mini marshmallows, crushed nuts, a molten Lindt ball for a lava center, vanilla frosting, or a scoop of ice cream on top.
Use a microwave-safe ceramic or glass mug. Avoid mugs with metallic trim or very narrow shapes. A mug of at least 10–12 oz capacity gives enough space for the cake to rise without spilling.
You can bake this in an oven-safe ramekin at 350 °F for about 12-15 minutes (time will vary). Texture will be slightly different (less “steamed” and more “baked”), but still delicious. Just make sure you use an oven safe ramekin here.
Peanut Butter Mug Cake
Ingredients
- 1 & 1/2 tbsp butter melted
- 1 & 1/2 tbsp peanut butter
- 1 egg yolk
- 2 tbsp brown sugar
- 1 & 1/2 tbsp milk
- 1/8 tsp vanilla extract optional
- 2 tbsp flour
- 1/8 tsp baking powder
- a pinch of salt
- vanilla frosting optional
Instructions
- Start by melting the butter in the mug, Add the peanut butter, and stir until combined. Add in the egg yolk, the brown sugar, salt, the milk, and the vanilla and stir again.1 & 1/2 tbsp butter, 1 & 1/2 tbsp peanut butter, 1 egg yolk, 2 tbsp brown sugar, 1 & 1/2 tbsp milk, 1/8 tsp vanilla extract, a pinch of salt
- Add the flour and the baking powder and stir one last time until it's completely smooth.2 tbsp flour, 1/8 tsp baking powder
- Cook in the microwave on high for 60 seconds. Top it with vanilla frosting and crushed peanuts or enjoy on it's own.vanilla frosting
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
Omgosh this was the best! We’ve tried a few mug recipes before, and typically they are mediocre leaving me craving a real dessert. This was incredible and totally took care of my sweet tooth!! We topped it with ice cream 🙂
Yay! I’m so glad this recipe could help your sweet tooth 😁
omg — to die for! yummmmm 🙂
It sure is! I have been having it religiously!! I need to find something else so that I can swtich between the two haha!
These look so good, what a good idea when your craving something and need it quick! lol
Absolutley! That’s my favorite part about this. Let me kno whow you like this peanut butter mug cake!
Chahinez