Keto Peanut Butter Chocolate Mug Cake

The Keto Peanut Butter Chocolate Mug Cake is a warm and gooey single-serve dessert made with almond flour, natural unsweetened peanut butter, unsweetened cocoa powder, egg, baking powder, and a keto-friendly sweetener. Microwaved in about 1 minute, it delivers rich chocolate flavor with a bold peanut butter taste and a soft, fudgy texture. High in satisfying fats and protein while keeping carbs low, it is best enjoyed fresh and warm but can be chilled for up to 2 days and gently reheated for a quick keto treat.

Course Dessert, Snack

Cuisine American, Keto

Keyword Chocolate, keto, low-carb, microwave dessert, Mug Cake, Peanut Butter, single serve

Prep Time 5

Cook Time 1

Total Time 6

Servings mug cake

Calories 430kcal

Equipment

10 to 12 ounce microwave-safe mug
measuring spoons
measuring cups
small whisk or fork

Ingredients

For the mug cake

3 tablespoons blanched almond flour fine or super-fine
1 tablespoon unsweetened cocoa powder natural or Dutch-processed
2 tablespoons natural unsweetened peanut butter smooth, with no added sugar
2 tablespoons granulated erythritol or erythritol-based keto sweetener, to taste
1 large egg at room temperature if possible
2 tablespoons unsweetened almond milk or unsweetened coconut milk
1 tablespoon salted butter melted and slightly cooled; use a pinch of salt if using unsalted butter
1/2 teaspoon baking powder gluten-free
1/2 teaspoon vanilla extract
1/8 teaspoon fine sea salt omit if your peanut butter is very salty

Optional mix-ins and toppings

1 tablespoon sugar-free dark chocolate chips optional, for extra gooey texture
1 tablespoon unsweetened whipped heavy cream optional, for serving
1/16 teaspoon flaky sea salt optional, to finish

Instructions

Add the almond flour, cocoa powder, erythritol, baking powder, and sea salt to a 10 to 12 ounce microwave-safe mug and whisk with a fork until the dry ingredients are evenly combined and no lumps of cocoa remain.
Stir in the egg, almond milk, melted butter, peanut butter, and vanilla extract until a smooth, thick batter forms, scraping down the sides of the mug so everything is fully incorporated.
Fold in the sugar-free chocolate chips, if using, making sure they are distributed throughout the batter rather than sitting only on top.
Tap the mug gently on the counter to level the batter and place it in the center of the microwave.
Microwave on high for 45 to 60 seconds, checking at the 45 second mark, until the top is just set, the edges look cooked through, and the center still looks slightly soft and fudgy.
Let the mug cake rest for 1 to 2 minutes to finish setting and cool slightly so it is warm but not scalding.
Top with whipped cream and a tiny pinch of flaky sea salt if desired, then serve the mug cake warm straight from the mug.
If you have leftovers, cover the cooled mug cake and refrigerate for up to 2 days, then gently reheat in the microwave for 10 to 15 seconds before serving.

Notes

Microwave strengths vary, so start with the shorter cook time and add a few seconds only if the center is still completely liquid, because a slightly underbaked center keeps the texture soft and fudgy. Use a natural peanut butter made only from peanuts and salt to avoid hidden sugars that can increase carbs. If you prefer a stronger chocolate flavor with less peanut intensity, reduce the peanut butter to 1 tablespoon and add an extra 1/2 tablespoon of cocoa powder, adjusting sweetener to taste. For advance prep, you can combine several portions of the dry ingredients in small jars, then just add the wet ingredients and microwave whenever a quick keto dessert craving hits.

Nutrition