3-Ingredient Peanut Butter Mug Cake

This peanut butter mug cake recipe is moist, fluffy, and full of rich peanut butter flavor. Made with just three ingredients, it takes less than a minute to bake.

Love mug cake recipes? Try my almond flour mug cake, protein mug cake, or chocolate chip mug cake next.

Everyone needs a go-to dessert that can be made with minimal effort when the cravings strike. My foolproof peanut butter mug cake recipe ticks those very boxes, and it’s become an almost nightly tradition!

Why I love this recipe

• It’s so darn easy. Just mix up your batter, pour it into your mug, and pop it in the microwave. It doesn’t get easier than this. 
• Easy to customize. There’s plenty of room to customize this recipe so you can make it different every time.
• Microwave and oven options. I prefer the microwave because it’s quick, but if I’m making mug cakes for the whole family, I always use the oven. 
• Secretly healthy. Like my cinnamon roll in a mug, this mug cake has a decent amount of protein and minimal sugar, though you’d never guess by how tasty it is.

★★★★★ REVIEW 

“Love this cake! It’s easy, it’s delicious, and the texture is good too. I do use a brown sweetener in it and sometimes add a little cinnamon to it. But even without the cinnamon, it’s great!” – Kristy

Ingredients needed

• Peanut butter. Make sure the peanut butter you use has a smooth and drippy texture. I like to use all-natural smooth by Skippy’s or Trader Joe’s. Peanut butter can be swapped for any type of nut or seed butter, like sunflower seed butter, almond butter, or cashew butter.
• Sugar. I used granulated white sugar, but if you’d prefer a more molasses flavor, use light brown sugar. Sugar substitutes will also work.
• Egg. For moisture and to bind the dry ingredients.
• Baking powder. It’s optional, but it gives the mug cake that extra fluffiness.
• Mix-ins. I’ve included a ton of suggestions in the variations section.

How to make a peanut butter mug cake

I’ve included step-by-step photos below to make this recipe easy to follow at home. For the full printable recipe instructions and ingredient quantities, scroll to the recipe card at the bottom of this post.

Step 1- Make the batter. In a small mixing bowl, add all your ingredients and stir to combine. Transfer the batter to a greased large mug, ramekin, or shallow bowl. 

Step 2- Microwave. Microwave the mug cake for 45 seconds- 1 minute, or until a toothpick inserted comes out clean. Remove the cake from the microwave and let it sit for one minute before serving.

Arman’s recipe tips

• Avoid overcooking. Everyone’s microwave is different, so the cooking time may vary. I recommend checking the cake every 30 seconds, and if it’s not cooked after 1 minute, microwave it in 20-second bursts until it’s fully cooked. 
• If you have a microwave safe cereal bowl, you can use that instead of a ramekin. This is a better option if you are worried that there may be overflow.
• If the batter looks too thick, I like to add 1-2 tablespoons of almond milk.

More delicious mug cakes to try

Originally published October 2020, updated and republished April 2024