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close up of peanut butter mug cake partially eaten
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5 from 1 vote

Peanut Butter Mug Cake (Keto)

This microwave peanut butter mug cake is nutty and rich yet keto, low carb, and gluten-free. It makes the perfect healthy breakfast or sugar-free dessert for one in 1-2 minutes. It has 6 ingredients: peanut butter, almond flour, butter, egg, sugar substitute, and chocolate chips... and will satisfy your cravings without guilt.
Keywords:breakfast recipes, keto peanut butter mug cake, mug cake recipes, peanut butter mug cake
Prep Time 1 minute
Cook Time 1 minute
Total Time 2 minutes
Servings 1
Calories627 kcal
Cost $0.20


  • Mug
  • microwave


  • 1 1/2 tbsp unsalted butter
  • 3 tbsp creamy peanut butter
  • 1 tbsp blanched almond flour
  • 1 large egg at room temperature
  • 2 tbsp Swerve granulated (or other)
  • 3 tbsp dark chocolate chips sugar-free or keto


  • In a 12-ounce mug, melt 1 tbsp of unsalted butter in the microwave, about 20-30 seconds, or until melted. Then, stir in the peanut butter, almond flour, egg, and sugar substitute such as Swerve or goldenmonk fruit until the mixture is combined.
  • In a small bowl, melt 1/2 tbsp of unsalted butter with 2 tbsp of chocolate chips in the microwave, about 45-60 seconds or until chocolate is melted. Stir very well until chocolate is smooth.
  • Pour melted chocolate on the top center of the peanut butter mixture and draw a few swirls with a chopstick or the tip of a pairing knife. Add about 1 tbsp of chocolate chips on top and microwave for about 60 to 80 seconds or until cooked and well set.
  • Let cool for at least 2 minutes before enjoying warm. If you want, serve with a scoop of vanilla ice cream on top.

Recipe Notes

  • Peanut butter: for any other nut butter, or Nutella
  • Sweetener: sugar, brown sugar, maple syrup, xylitol, etc
  • Egg: 1/4 cup mashed banana = 1/3 cup applesauce
  • Almond flour -- use coconut flour instead, about 1/3 of the amount for almond flour (or 1 tsp)
Cooking/baking tips 
  • To avoid spills, be sure to use a mug that is large enough, as the batter will rise a lot in the microwave. I suggest using at least a 10 to 12-ounce mug for this recipe because the batter will rise quite high during the cooking process.
  • Keep a close eye on the mug cake while it is in the microwave to avoid spillage.
  • Cook it just until the center is just set. The final cooking time will depend on 1) The potency of your microwave. On a 1200 Watts microwave, it takes around 1 minute. 2) If your mug is wider than taller. Wider mugs will have the cake batter spread out and so, it will cook faster than if in a deep or tall mug. In addition, it will take more time to bake (10-15 minutes) than cook it in the microwave (1-2 minutes). Stick to standard shaped mugs. Why? Because mugs that are too tall/skinny or have an odd shape may cause the cake not to cook evenly. I find wide mugs cook this type of cake better and faster! Do not overcook the cake. A few seconds can make a big difference. But if you find your cake not fully cooked, cook it a little longer at 10-15 second intervals.
Can it be baked in the oven?
Yes, it can! For that, preheat the oven at 350 degreesF/180 degrees C and bake our peanut butter cake in a mug for 10-15 minutes. It's key to not omit adding the almond flour to the peanut butter mixture in order to give this healthy mug cake a real cake structure. But it will cook much faster in the microwave, about 1-2 minutes!
Eat this peanut butter mug cake warm to enjoy the melted chocolate goodness. But you can cover the mug once the cake cools and store in the fridge for up to 24 hours. Eat cold, or heat covered in the microwave for about 20-30 seconds, or until warm.


Calories: 627kcal | Carbohydrates: 24g | Protein: 21g | Fat: 56g | Saturated Fat: 21g | Cholesterol: 209mg | Sodium: 285mg | Potassium: 372mg | Fiber: 10g | Sugar: 5g | Vitamin A: 770IU | Calcium: 60mg | Iron: 2mg
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