Quick Banana Peanut Butter Mug Cake (High Protein, Single Serve Dessert)
Table of contents
There are mug cakes, and then there is this one. A cozy, fluffy banana cake with a molten peanut butter center that oozes the second your spoon dives in, ready in under two minutes.
This banana peanut butter mug cake is the snack I make when the toddler is napping, the house is quiet, and my sweet tooth suddenly wakes up. It is dessert for one, made in a mug, with no oven and no pile of dishes waiting for you after.
It has that nostalgic banana bread energy, soft and fluffy with a warm peanut butter core that makes it feel extra special. Bonus points because it is high protein, naturally sweetened, and easy to customize based on what you already have in your kitchen.
This post may contain affiliate links, please read our privacy policy for details.
Why You’ll Love This Banana Peanut Butter Mug Cake
• Ready in just a few minutes
• Single serve and no leftovers
• Soft banana cake with a gooey peanut butter center
• High protein and surprisingly filling
• Microwave or oven friendly
• Perfect for a quick snack or dessert
If you love banana bread and peanut butter, this one checks every box.
What Makes the Center Molten and Gooey
The key to this mug cake is layering.
Half of the batter goes into the mug first, then a spoonful of peanut butter gets dropped right into the center. The remaining batter covers it, allowing the cake to cook around the peanut butter while the center stays warm and molten.
Letting the mug cake rest for a minute after cooking helps the texture settle while keeping the center gooey.
Key Tips for the Best Mug Cake Texture
Start with less microwave time
Begin at 60 seconds, then add time in 10 second intervals. The top should look just set while the inside still feels soft.
Use a large mug or ramekin
The batter rises as it cooks, so a larger mug helps prevent overflow.
Do not overmix the batter
Stir just until combined for a fluffy, tender texture.
Watch your protein powder
Some powders absorb more liquid. If the batter looks thick or dry, add a splash or two of milk.
Let it rest before eating
Give it one to two minutes after cooking. The flavor improves and the texture finishes setting.
Ingredient Swaps & Variations
No protein powder -> Use 2 tablespoons oat flour or almond flour and add ¼ teaspoon cinnamon
No almond flour -> Oat flour, cassava flour, or all purpose flour all work
No peanut butter -> Almond butter, sunflower seed butter, or a square of dark chocolate
Dairy free -> Use plant based protein powder and dairy free milk
Want it sweeter -> Add mini chocolate chips or drizzle maple syrup after cooking
This mug cake is very forgiving and easy to adjust.
Storage, Freezing, & Meal Prep
Storage
Let cool completely, then cover and refrigerate for up to 2 days. Reheat in the microwave for 15 to 20 seconds.
Freezing
Not ideal because of the molten center, but it can be frozen for up to 1 month. Thaw overnight in the fridge and reheat before eating.
Meal prep tip
Mix the dry ingredients in advance and store in a sealed container. When ready, add banana, egg, and wet ingredients for a fast mug cake.
Frequently Asked Questions
Yes. The microwave is the fastest option and works perfectly. Start at 60 seconds and adjust as needed.
Slightly undercook the mug cake and let it rest for one minute before eating.
Yes. Bake at 350°F for 15 to 18 minutes until the top is set and the center is still soft.
A large microwave safe mug or a small ramekin works best.
Yes. Replace the protein powder with additional flour and adjust liquid if needed.
You May Also Like
Quick Banana Peanut Butter Mug Cake
Ingredients
- 1/2 banana ripe and mashed
- 1 egg
- 1 scoop vanilla or unflavored protein powder
- 1 tbsp almond flour
- 1 tbsp maple syrup
- 1/4 tsp baking powder
- 1/2 tsp vanilla extract
- Pinch of salt
- 1 tbsp peanut butter for the molten center
- 1-2 tbsp milk of choice if batter is thick
Instructions
- In a mug or small bowl, mash banana and mix in egg, maple syrup, and vanilla.
- Stir in protein powder, almond flour, baking powder, and salt until just combined.
- Add milk if needed for a cake-batter consistency.
- Pour half the batter into a greased mug or ramekin. Add the peanut butter in the center, then top with remaining batter.
- Microwave for 60–75 seconds or bake at 350°F for 15–18 minutes until just set on top.
- Let cool slightly and enjoy warm!
Notes
• Use a large mug or ramekin to prevent overflow.
• Let the mug cake rest for one to two minutes before eating for best texture.
• Add milk if the batter looks thick, especially when using absorbent protein powders.
• Best eaten fresh, but leftovers can be refrigerated for up to 2 days and reheated gently.
