Desserts · Part 3 of 3: Tips & recipe card

Molten Chocolate Peanut Butter Lava Mug Cake Tips, FAQ & printable recipe

Name: Molten Chocolate Peanut Butter Lava Mug Cake
Prep time: 5 min
Cook time: 2 min
Total time: 7 min
Cuisine: American
Ingredients: 4 tbsp all-purpose flour; 2 tbsp granulated sugar; 2 tbsp unsweetened cocoa powder; 1/2 tsp baking powder; 4 tbsp milk; 2 tbsp unsalted butter, melted; 1/2 tsp vanilla extract; 2 tbsp creamy peanut butter; Powdered sugar, for dusting, to taste; Whipped cream, for serving

By Clara Weller · Oct 21, 2026

Molten chocolate peanut butter lava mug cake with powdered sugar and whipped cream

Prep: 5 min
Cook: 2 min
Total: 7 min
Serves: 1

Tips for success

For a more indulgent treat, add a few chocolate chips or a square of dark chocolate on top of the peanut butter before microwaving; it will melt and create an extra gooey center.

If you prefer a crispier top, sprinkle a little extra sugar on the batter before cooking. The mug cake is best enjoyed fresh, but if you have leftovers, they can be reheated in the microwave for a few seconds to restore the molten texture.

When measuring the peanut butter, use a spoon to scoop it out and level it off to ensure you have the right amount. If the peanut butter is too stiff, warm it in the microwave for a few seconds to make it easier to dollop.

For a decorative touch, drizzle a little melted chocolate over the top after dusting with powdered sugar. The cake is delicious on its own, but a scoop of vanilla ice cream on the side is also a great pairing.

Variations

Nutella Lava: Replace the peanut butter with 2 tablespoons of chocolate-hazelnut spread for a hazelnut twist. The spread will melt into a rich, chocolatey lava center. Omit the powdered sugar or use a dusting of cocoa powder instead.
S'mores Mug Cake: Add 2 tablespoons of crushed graham crackers to the batter and use a marshmallow or marshmallow fluff instead of peanut butter. After microwaving, top with a few mini marshmallows and broil briefly for a toasted effect, if desired.
Peanut Butter Cup: Chop a peanut butter cup and place it in the center of the batter instead of peanut butter. The candy will melt into a gooey, chocolate-peanut butter lava. You can also sprinkle extra chopped peanut butter cup on top before serving.
Banana Split: Mash half a ripe banana and stir it into the batter before microwaving. Reduce the milk to 3 tablespoons to adjust the consistency. Use chocolate chips or a spoonful of caramel sauce instead of peanut butter for a fruity twist.

Storage and make-ahead

Fridge: Store any leftover mug cake in an airtight container in the refrigerator for up to 2 days.
Freezer: Freezing is not recommended as the texture will change upon thawing.
Reheat: Reheat in the microwave for 15-20 seconds until warm, but the center may not be as molten as when fresh.

The mug cake is best enjoyed immediately after cooking, as the molten center will set as it cools. If you have leftovers, you can store them in an airtight container in the refrigerator for up to 2 days. To reheat, microwave the cake for 15-20 seconds until warm, but note that the center may not be as molten as when fresh.

This recipe is so quick that making it ahead is not necessary. However, you can pre-mix the dry ingredients (flour, sugar, cocoa powder, baking powder) in a small container or resealable bag.

When ready to make the cake, just add the wet ingredients and microwave. This makes it even easier to whip up a single-serving dessert on demand.

Serving ideas

Serve the mug cake straight from the microwave, as the contrast between the warm cake and the molten peanut butter is best when fresh. Dust with powdered sugar and add a dollop of whipped cream for a classic finish. The cake can be eaten directly from the mug with a spoon, making it a perfectly portable dessert for a cozy night in.

For a more polished presentation, transfer the cake to a small plate or bowl before serving. Pair it with a glass of cold milk or a scoop of vanilla ice cream to balance the richness.

The cake is also delicious with a drizzle of chocolate sauce or a sprinkle of sea salt to enhance the flavors. However you choose to serve it, this mug cake is sure to satisfy a chocolate and peanut butter craving in minutes.

Frequently asked questions

Can this mug cake be made in a regular oven?

Yes, this recipe can be adapted for a conventional oven. Preheat the oven to 350°F (175°C). Pour the batter into a small oven-safe ramekin and bake for about 12-15 minutes, or until the top is set. The center should still be slightly soft to ensure a molten texture. Keep in mind that the baking time may vary, so check for doneness with a toothpick.

Why is the peanut butter not melting in the center?

If the peanut butter doesn't melt, it may be because the cake is undercooked or the peanut butter was too cold. Make sure to use creamy peanut butter at room temperature. Also, ensure the microwave time is sufficient—70 seconds is typical, but you may need to add 10-15 seconds for a lower-wattage microwave. The center should be soft and molten when done.

Can this recipe be doubled to make two mug cakes?

Yes, the recipe can be easily doubled. Simply double all ingredients and divide the batter between two mugs. Microwave each mug separately, as cooking them together may result in uneven cooking. Adjust the cooking time as needed, as two mugs may require a few extra seconds in the microwave.

What can be used instead of peanut butter?

For a nut-free version, sunflower seed butter or cookie butter works well. You can also use chocolate-hazelnut spread, caramel sauce, or a marshmallow fluff for different flavor profiles. Just keep in mind that the texture and meltiness may vary slightly depending on what you choose.

Why does the cake overflow in the microwave?

Overflow usually happens if the mug is too small or the batter is overfilled. Use a mug that holds at least 12 ounces and fill it only halfway with batter. Also, be sure to mix the batter thoroughly to avoid pockets of dry ingredients that can cause uneven rising. If overflow is a recurring issue, reduce the batter amount slightly.

Recipe card

Molten Chocolate Peanut Butter Lava Mug Cake

Prep 5 minCook 2 minTotal 7 minServes 1

Ingredients

4 tbsp all-purpose flour
2 tbsp granulated sugar
2 tbsp unsweetened cocoa powder
1/2 tsp baking powder
4 tbsp milk
2 tbsp unsalted butter, melted
1/2 tsp vanilla extract
2 tbsp creamy peanut butter
Powdered sugar, for dusting, to taste
Whipped cream, for serving

Instructions

In a microwave-safe mug, combine the flour, sugar, cocoa powder, and baking powder. Add the milk, melted butter, and vanilla extract. Whisk with a small whisk or fork until the batter is smooth and glossy, with no dry streaks. Make sure to scrape the bottom and sides of the mug to fully incorporate all the dry ingredients.
Spoon the creamy peanut butter into the center of the batter. Do not stir it in; let it sit on top and sink slightly into the middle. This creates the molten lava center as the cake bakes around it.
Place the mug in the microwave and cook on high for 70 seconds. The cake will puff up around the edges and look set on the surface while the center remains molten. The exact time may vary depending on the microwave wattage, so adjust by a few seconds if needed.
Carefully remove the mug from the microwave (it will be hot). Dust the top generously with powdered sugar. Optionally, top with a dollop of whipped cream. Dig a spoon straight into the center to reveal the molten peanut butter lava and enjoy immediately.

Contains: gluten, milk, peanuts, eggs

Estimated nutrition per serving

Calories: 650
Protein: 12 g
Carbohydrates: 75 g
Fat: 35 g

Automatic estimate from the ingredient list, not laboratory-verified.

Next recipe

A glass dish of Turkish Kadayıflı Muhallebi with golden crispy kadayıf and walnuts on top, creamy pudding visible beneath.

Desserts · 2 h 45 min

Turkish Kadayıflı Muhallebi: Crispy & Creamy Pudding

See the recipe → →

This recipe is based on a short cooking video and is published under the pen name Clara Weller. It was checked before publication, but errors can slip through. Nutrition, when shown, is an estimate. Read more in our editorial policy and on our food safety page.