Flourless Peanut Butter Mug Cake

photo of a Flourless Peanut Butter Mug Cake topped with caramel sauce

I haven’t had much time to bake lately, but that hasn’t stopped me from craving sweets. So once again, my mug cakes came to the rescue.
photo of a Flourless Peanut Butter Mug Cake
Because it’s flourless, the mug cake does not rise as high as my other mug cakes. I had to give it a boost in the mug so you can see the cake. That is also why I ended up putting it on a plate after.

Taking the same idea behind the flourless peanut butter muffins and flourless Nutella muffins, I used banana as a substitute.
close-up photo of a mug cake on a plate
This cake came out really yummy. Moist, soft and peanut buttery. I decided to add a little caramel on sauce on top too.
photo of a fork cutting off a piece of cake

I use some salted caramel sauce from Trader Joe’s. I love how thick it is and the interplay of the salty and sweet. The sauce was so good, I added some more…

You can check out all my mug cake recipes here.

Flourless Peanut Butter Mug Cake

Prep Time: 4 minutes
Cook Time: 1 minute
Total Time: 5 minutes
Course: Dessert
Cuisine: American
Servings: 1

This easy mug cake is moist, soft and peanut buttery.


  • 2 tbsp peanut butter use store bought and not natural
  • 1/2 of a whisked large egg about 1 1/2 - 2 tbsp
  • 1/2 tbsp granulated sugar
  • 1/2 of a large overripe mashed banana
  • 1/4 tsp baking powder


  1. Whisk all ingredients in a microwave-safe mug until batter is smooth and no banana chunks remain.

  2. Cook in microwave for approximately 1 minute and 20 seconds, or until batter is cooked and no longer gooey. Careful not to overcook. I started with 1 minute, and then added another 20 seconds. Let cool slightly in mug before eating. You can also dump out onto a plate and serve topped with salted caramel sauce.

All images and content are © Kirbie's Cravings.

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