Keto Molten Peanut Butter Mug Cake

If you’re craving something sweet, chocolatey, and ready in under five minutes, this keto molten peanut butter mug cake is about to become your new favorite dessert.

It’s a rich chocolate cake made in a mug with a warm, gooey peanut butter center that oozes out when you dig your spoon in. Honestly, it’s hard to believe something this good can be low carb.

The whole thing is keto friendly, sugar free, and super easy to make. You don’t need an oven, special equipment, or a lot of time.

Just mix a few simple ingredients, pop it in the microwave, and you’ve got a single serving dessert that feels way more indulgent than it actually is.

If you’ve been looking for a quick keto treat that actually satisfies a real chocolate craving, this is the one.

Why You’ll Love This Recipe

Molten Peanut Butter Center – That warm oozing peanut butter core melting into rich chocolate cake is pure dessert heaven in every single bite.

Ready in Minutes – From start to finish this entire mug cake takes under 5 minutes to make not counting the freezer time.

Incredible Chocolate and Peanut Butter Combo – The deep cocoa flavor paired with creamy sweet peanut butter is a classic combo that never gets old.

Recipe Ingredients

For the Peanut Butter Center

• 1 tbsp Creamy Peanut Butter
• 1 tsp Powdered Erythritol

For the Chocolate Cake

• 3 tbsp Almond Flour
• 1 tbsp Unsweetened Cocoa Powder
• 2 tbsp Granulated Erythritol
• 1/2 tsp Baking Powder
• 1 Large Egg
• 1 tbsp Melted Coconut Oil
• 1 tbsp Heavy Cream
• 1/2 tsp Vanilla Extract
• Pinch of Salt

How To Make

Step 1

In a small bowl, stir together the peanut butter and powdered erythritol until combined. Roll it into a small ball and place it in the freezer for at least 15 minutes so it firms up and holds its shape.

Step 2

In a microwave-safe mug (at least 12 oz), whisk together the almond flour, cocoa powder, granulated erythritol, baking powder, and salt until fully combined with no lumps.

Step 3

Add the egg, melted coconut oil, heavy cream, and vanilla extract to the mug. Stir until the batter is smooth and evenly mixed.

Step 4

Spoon about half of the batter out into a small bowl temporarily. Place the frozen peanut butter ball directly in the center of the remaining batter in the mug, then gently spoon the reserved batter back on top so the peanut butter is fully covered.

Step 5

Microwave on high for 70 to 80 seconds, until the chocolate cake is set around the edges but the center still has a slight jiggle.

Step 6

Let the mug cake rest for 1 minute, then dig in with a spoon from the center. The peanut butter core should be warm, melty, and oozing into the rich chocolate cake.

Tips

Freeze the Peanut Butter Ball Properly

Don’t skip the freezer step or cut it short. If the peanut butter ball isn’t firm enough, it will just melt into the batter during microwaving and you won’t get that molten oozing center.

15 minutes is the minimum, but 20-25 minutes works even better. You want it to feel solid when you press it lightly with your finger. That way it holds its shape long enough for the cake to set around it while the center stays gooey.

Use a Big Enough Mug

A 12 oz mug is the minimum here, but if you have a wider one that’s even better. The batter rises a lot in the microwave and a small mug will cause it to overflow and make a mess.

A wider mug also helps the cake cook more evenly. In a narrow mug, the edges can overcook while the middle stays raw – and not in the good molten way.

Make Sure the Peanut Butter Ball Is Fully Covered

When you place the frozen peanut butter ball in the center and spoon the remaining batter on top, make sure it’s completely buried. If any part of it is exposed or too close to the surface, it will just melt outward instead of staying trapped inside.

Press the ball down gently into the bottom layer of batter first, then carefully spread the reserved batter over the top so there’s an even layer covering it on all sides.

More Recipes

• Keto 90-Second Chocolate Mug Cake
• Keto Funfetti Mug Cake
• Keto Chocolate Peanut Butter Mousse Cake
• Keto Peanut Butter Swirl Brownies

Frequently Asked Questions

Why does the peanut butter ball need to go in the freezer first?

Freezing the peanut butter ball helps it hold its shape so it stays in the center of the cake instead of melting into the batter right away. If you skip this step, the peanut butter will mix into the chocolate batter during cooking and you won’t get that gooey, molten center when you dig in.

Fifteen minutes in the freezer is usually enough, but if you have time, leaving it in a bit longer won’t hurt. The firmer it is, the better your molten center will turn out.