This microwave Peanut Butter Mug Cake is rich, gooey, and ready in just minutes, no oven needed! It’s a quick and satisfying single-serve dessert for peanut butter lovers. I love that I can satisfy a sweet craving without baking a whole cake! And, it is so easy, just like my other 15 Minute Easy Desserts you will want to try, too! Craving chocolate instead? My Chocolate Syrup Mug Cake is just as easy and full of rich, chocolatey flavor.
Key Ingredients & Substitutions
- Peanut Butter: I used creamy peanut butter for a smooth texture.
- Butter: Butter (I prefer unsalted) adds a rich, creamy flavor and adds moisture, keeping the cake tender. If using salted butter, you may want to reduce the amount of salt in the recipe.
- Brown Sugar: Light brown sugar adds moisture to the mug cake. It also gives it a caramel-like richness. Dark brown sugar could work, too, just expect a more intense flavor.
- Egg Yolk: You will only use the egg yolk in this mug cake. It adds fat and moisture without the extra protein from the egg white. But, don’t let the egg white go to waste! Use it for another recipe, like fried ice cream or almond paste.
- Milk: If you don’t have whole milk, 2%, 1%, or even skim milk would work, too. But using lower-fat milk might make the cake turn out a little less rich and a bit drier.
- Chocolate Chips: Mini chocolate chips add little bursts of melty chocolate throughout the mug cake, making each bite extra delicious. I love the combination of peanut butter and chocolate. For an optional topping, try sprinkling a few more chips on top before microwaving.
Can I Use Crunchy Peanut Butter Instead Of Creamy?
Yes! Crunchy peanut butter works just fine in this mug cake. It will add little bits of peanut throughout the cake, which gives it extra texture and a slightly nuttier bite. Just be sure to stir it in well so the batter mixes evenly.
How To Keep Peanut Butter Mug Cake Moist and Avoid Dryness
To keep your peanut butter mug cake moist, avoid overcooking it. So, microwave just until the top looks set but still a bit glossy, usually around 40 to 55 seconds. Microwaves vary, so start checking early, at the 40-second mark. If it still feels dry, try adding a splash more milk or cutting the cooking time a little shorter next time.
How To Serve Peanut Butter Mug Cake
This mug cake is best served warm, straight from the mug; it’s soft, gooey, and full of peanut butter flavor! You can enjoy it as-is or add a little something on top. But hurry! Grab a spoon and dig in while it is still warm!
- A dollop of whipped cream
- A drizzle of chocolate syrup or warm peanut butter
- A scoop of no-churn vanilla ice cream for an extra treat (or, better yet, try it with my chocolate peanut butter ice cream!)
- Extra chocolate chips right after microwaving
How to Store a Peanut Butter Mug Cake
Mug cakes are best eaten fresh, but if you have leftovers, let the cake cool completely. Then, cover the mug tightly with plastic wrap or transfer the cake to an airtight container. Store it in the refrigerator for up to 2 days. Reheat in the microwave for about 10–15 seconds before enjoying. Just know it may be a little drier than when freshly made.
Peanut Butter Mug Cake
Ingredients
- 3 tablespoons creamy peanut butter
- 1 tablespoon unsalted butter
- 2 tablespoons light brown sugar, packed
- 1 large egg yolk, lightly beaten
- 1 tablespoon whole milk
- ½ teaspoon pure vanilla extract
- 3 tablespoons all-purpose flour
- ¼ teaspoon baking powder
- 1 pinch kosher salt
- 1 tablespoon mini chocolate chips, plus more for topping (optional)
Instructions
- Lightly coat the inside of an 8-ounce microwave-safe mug with nonstick cooking spray. Set aside.
- In a small microwave-safe bowl, combine peanut butter and unsalted butter. Microwave for about 15–20 seconds, just until softened, but not bubbling. Stir together until completely smooth.
- Add light brown sugar to the warm peanut butter mixture and stir until combined.
- Add lightly beaten egg yolk, milk, and vanilla. Stir until the mixture is fully smooth and combined.
- Add flour, baking powder, and salt. Stir gently until no dry spots remain; do not overmix.
- Fold in mini chocolate chips.
- Spoon the batter into the prepared microwave-safe mug. If desired, sprinkle a few extra chocolate chips on top.
- Microwave on high for 40 to 55 seconds, depending on your microwave's strength. The top should look just set but still slightly glossy in the center. Start checking at 40 seconds to avoid overcooking, as the cake can dry out quickly.
- Let the mug cake cool for about 2 minutes before serving.
- Enjoy warm, straight from the mug.
Did you make this recipe?
Thank you for making my recipe! You took pictures, right? Well go ahead and post them on Instagram! Be sure to mention me @iambaker and use the hashtag #YouAreBaker.
What the Test Kitchen had to say about this recipe:
Autumn
This totally hit the spot! It is quick and easy, and it satisfied my dessert craving!
Elizabeth
I love peanut butter, and now I LOVE this mug cake. I kept digging in for more…What a great idea!
Stephanie
I did not expect this mug cake to be this good from a microwave! The texture and flavor was amazing, especially if you love peanut butter and chocolate.
Bella
This is almost too easy…I loved it so much and have a feeling I will be making this a lot!
