Peanut Butter Mug Cake

By Arman Liewupdated on Feb 01, 2026

Total Time 2

Servings 1 mug cake

This post may contain affiliate links. See my disclosure policy.

My 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.

Table of Contents

My easy peanut butter mug cake is so satisfying
Key Ingredients
How to make a peanut butter mug cake
Arman’s recipe tips
Peanut Butter Mug Cake (Recipe Card)
More simple mug cake recipes

My easy peanut butter mug cake is so satisfying

Everyone needs a go-to dessert that can be made with minimal effort when the cravings strike, and my foolproof peanut butter mug cake recipe ticks those very boxes.

This dessert almost made it into my first cookbook, but I was still testing and tweaking it right up against my deadline. It didn’t make the final pages, but fortunately, I can share it with you now. Here’s why you’ll love it:

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 use a brown sweetener in it and sometimes add a little cinnamon. But even without the cinnamon, it’s great!” – Kristy

Key Ingredients

ingredients for a peanut butter mug cake.

Here’s what goes into this peanut cake, along with my kitchen notes. Full measurements are in the recipe card below.

Peanut butter. Make sure the peanut butter you use has a smooth and drippy texture. I prefer all-natural smooth peanut butter from Skippy or Trader Joe’s. Peanut butter can be substituted with any nut or seed butter, such as 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. Several readers also asked for a keto option, so I tested it with allulose, and it turned out really well.
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 numerous suggestions in the variations section.

How to make a peanut butter mug cake

Step 1- Make the batter. In a small mixing bowl, combine all ingredients.

Step 2- Microwave. Transfer the batter to a greased large mug, ramekin, or shallow bowl. Microwave the mug cake for 45 seconds or until a toothpick inserted into the center comes out clean.

Step 3- Remove the cake from the microwave and let it sit for one minute before serving.

How to make this in the oven

If you’d prefer to bake the mug cake in the oven, it’s easy. Preheat the oven to 350F (180C) and grease a 6- or 8-inch ramekin with cooking spray. Make the batter, pour it into the ramekin, and bake for 8-10 minutes, or until a toothpick inserted in the center comes out clean.

Arman’s recipe tips

Avoid overcooking. Microwaves vary, so cooking times aren’t consistent. I recommend checking the cake every 30 seconds. If it’s not cooked after 1 minute, microwave it in 20-second bursts until fully cooked.
Your bowl matters. If you have a microwave-safe cereal bowl, you can use that instead of a ramekin. This is a better option if you are concerned about overflow. Opt for a bowl or mug that is at least 6 ounces deep.
Adjust the batter. If the batter looks too thick, I like to add 1-2 tablespoons of almond milk.
Add mix-ins. I like to add chocolate chips to make a peanut butter chocolate chip mug cake. Fresh or frozen berries are also great!