Peanut Butter Brownie in a Mug

Okay, listen — I just discovered the easiest way to satisfy a chocolate and peanut butter craving in under two minutes.
No, really — it’s a mug brownie that somehow tastes like a fudgy peanut butter brownie and it takes zero drama.
I made it late at night and yes, I judged my own life choices while I ate it — then I made it again the next day because science.
This recipe uses a handful of pantry staples, a regular mug, and a microwave; no oven or fancy gear required.
Stick around and I’ll show you exact ingredients, method, tips, and fun toppings — plus a tiny rant about why store-bought brownies don’t always behave.
If you like quick single-serve treats, you’ll also enjoy my dinner roll obsession over at soft and buttery dinner rolls recipe.

Why You’ll Love This Recipe

• Ready in minutes: microwave magic means dessert fast.
• Minimal dishes: you only use one mug and one spoon.
• Customizable: swap peanut butter types or add chocolate chips.
• Satisfying and portion-controlled: perfect when you want a treat without committing to a whole pan.
• Pantry-friendly: uses common staples so you won’t need a special grocery run.
• Great for diets: easily vegan or lower-sugar with substitutions.

Seriously, this mug brownie hits a neat sweet spot between speedy and satisfying. You eat it hot, fork-free, and you don’t have to commit to baking an entire pan. Isn’t that the dream when you want dessert immediately but also want to pretend you made a responsible choice? In my tests, creamy peanut butter adds richness, balances the cocoa, keeps the center moist, and cuts the need for extra oil or butter every single time.

Ingredients You’ll Need

• 2 tablespoons peanut butter
• 1 tablespoon cocoa powder
• 2 tablespoons sugar
• 1/4 teaspoon vanilla extract
• 1 egg (or egg substitute for vegan)
• 2 tablespoons flour
• A pinch of salt

How to Make (Step-by-Step)

STEP 1

In a microwave safe mug, combine peanut butter, cocoa powder, sugar, vanilla extract, and egg. Mix until well combined.

STEP 2

Stir in flour and a pinch of salt until smooth.

STEP 3

Microwave on high for 1 minute.

STEP 4

Allow to cool slightly before enjoying.

Pro Tips for the Best Results

• Use creamy peanut butter for a smoother texture; natural jars work too but stir well first.
• Don’t overcook—microwaves vary, so check at 50 seconds and add time if needed.
• Try almond or cashew butter if you want a twist or need a peanut-free option.
• Sweetness control: use less sugar or a sugar substitute to lower sweetness.
• Add chocolate chips on top before microwaving for melty pockets.
• Serve warm with a scoop of ice cream to level up indulgence.

One time I used crunchy peanut butter and the texture surprised me in a very good way. The tiny bits added interest and extra peanut flavor pockets, so don’t automatically rule it out. If you fear sugar, try a blending trick: swap half the sugar with unsweetened applesauce and reduce added liquid elsewhere. I often tweak the sugar level for late-night snacks and I still get the emotional satisfaction of a brownie every single time.

Fun Variations & Topping Ideas

Variations:

• Vegan: swap egg for mashed banana or flax egg.
• Double chocolate: stir in a tablespoon of melted chocolate.
• Peanut butter swirl: drop extra dollop and swirl before cooking.
• Protein boost: add a scoop of chocolate protein powder.

Want more protein; I toss a half scoop of chocolate protein powder in and it works surprisingly well. Be careful with flavored powders because they can compete with the peanut butter, but adding mashed banana and a pinch of cinnamon creates a tasty peanut-butter-banana spin. Adding espresso or instant coffee powder makes the chocolate notes pop and brightens the flavor without adding sugar. Try it cautiously and write down the tweaks you prefer each time.

Toppings:

• Sea salt flakes
• Chopped peanuts
• Mini marshmallows
• Drizzle of honey or syrup
• Whipped cream or ice cream

Toppings change the mood instantly and require almost no effort; a sprinkle of flaky sea salt pairs beautifully with peanut butter to highlight sweet and savory notes. Warm marshmallows melt into delightful pockets, while chopped peanuts add crunch and texture contrast. If you want ultra-indulgent, top with a scoop of vanilla ice cream and watch the melty mess become a masterpiece. For a healthier crunch, try roasted chickpeas or toasted oats as a topping.

Storing and Reheating

If you make the mug brownie ahead or have leftovers, store the mug covered in the refrigerator for up to two days. To reheat, microwave for 20 to 30 seconds until warm; avoid nuking too long or it will dry out. You can also scoop the cooled brownie into a bowl and warm it gently for a softer texture.

Freezing works better than you’d expect: scoop cooled brownie into a freezer-safe container and freeze for up to one month. Thaw in the refrigerator overnight or at room temperature for a few hours before reheating. To reheat from frozen, microwave for 45 to 60 seconds at reduced power, checking, rotating, and avoiding overcooked edges. If you plan to pack one for lunch, store it in an insulated bag with a cold pack to maintain texture.

Leftover ideas

Stir leftover brownie into your morning oatmeal for a dessert-y breakfast boost. Use it as an ice cream topping or crumbled over yogurt. Or make brownie milkshake by blending with milk and a scoop of vanilla ice cream.

Leftovers rarely last long in my house but when they do, I turn them into portable snacks. Scoop into a jar, add Greek yogurt, and top with fresh fruit for an instant parfait. Or crumble and fold into cookie dough for a peanut butter brownie cookie experiment. My favorite hack: stir a spoonful into hot milk for a creamy, chocolatey drink that tastes like dessert in a mug, all over again — true story, trust me.

Frequently Asked Questions (FAQ)

Can I make this without an egg?

Yes — use a mashed banana or a flax egg to make it vegan. Texture will change slightly but I liked the banana version for a softer crumb. Try 1 tablespoon ground flax mixed with 3 tablespoons water for a good flax egg.

Can I bake this in the oven?

Absolutely, but you lose the one-minute magic. Bake at 350°F in a small ramekin for about 12 minutes, checking often. Expect a more cake-like texture when you use the oven.

How can I reduce sugar?

Swap the sugar for a sugar substitute or cut the amount by half. Use natural sweeteners like maple syrup, but reduce other liquids slightly to compensate.

Can I halve the recipe if my mug is huge?

FAQ bonus: yes, you can halve the recipe if your mug looks enormous and you want a smaller treat. I used to double the batch like a glutton until I learned portion control, and now I appreciate that single-serve satisfies. Can you add more butter? Sure, but you will change the texture and calories, so proceed with caution. No; covering traps steam and makes the edges tough, so avoid it and enjoy, carefully, of course.

Comparative and Opinion-Based Commentary

I used to buy microwave mug cakes that tasted artificial and dry; this recipe fixed that problem. Compared to boxed mixes, you control the peanut butter quality and the sugar level, which matters a lot. If you want bakery-level brownies you may still prefer a pan, but for instant gratification, this beats prepackaged options. I recommend using a higher-quality cocoa powder and a natural peanut butter for honest flavor that tastes homemade every single time.

FYI, the recipe scales strangely if you double it; microwave heating becomes uneven, so I don’t recommend doubling in one mug. Instead, make two separate mugs and cook them separately for consistent texture. If you cook for guests, prepare ingredients in bowls and let everyone assemble their own; it makes for a fun, interactive dessert moment. Go on, try it tonight, rate it, and tell me what topping won your heart — I’ll reply to comments, promise.

Conclusion

This Peanut Butter Brownie in a Mug delivers fast, fudgy, peanut-buttery comfort with almost zero fuss. You get a single-serve dessert that feels indulgent but still fits into busy nights or snack attacks. Give it a try, leave a comment, and don’t forget to rate the recipe if you make it. For a slightly different take with chocolate-focused ratios, check out Chocolate Peanut Butter Mug Cake – FIVEheartHOME for extra ideas.