Whenever I bake these peanut butter brownies, that smell of chocolate fills the kitchen, and I instantly remember why I love baking in the first place.
This recipe started out as a happy accident. I had planned on making classic brownies one afternoon, but halfway through, I noticed half a jar of peanut butter sitting on the counter. I swirled a few spoonfuls into the batter without thinking — and the result was so good that it’s now the only way I make brownies.
These brownies have that perfect mix of fudgy chocolate and creamy peanut butter — soft in the middle, crisp on the edges, and just rich enough to make every bite feel indulgent.
Why You’ll Love These Brownies
They’re the best kind of homemade dessert — simple, comforting, and guaranteed to disappear fast. The chocolate base is dense and rich, but the peanut butter swirl lightens it up just enough.
The best part? You don’t need anything fancy. No mixer, no complicated steps — just a bowl, a whisk, and a little patience while they bake. If you can stir, you can make these brownies.
They’re perfect for bake sales, birthdays, or just when you need something sweet that feels a little special without being fussy.
Ingredients (Makes 12 Brownies)
- ½ cup unsalted butter (1 stick)
- 1 cup granulated sugar
- 2 large eggs
- 1 teaspoon vanilla extract
- ⅓ cup unsweetened cocoa powder
- ½ cup all-purpose flour
- ¼ teaspoon salt
- ½ teaspoon baking powder
- ½ cup creamy peanut butter
- 2 tablespoons powdered sugar (for mixing with peanut butter)
Optional: ¼ cup chocolate chips for extra texture
Melt the Butter and Mix
Start by melting the butter in a small saucepan over low heat or in the microwave. Let it cool slightly — warm, not hot.
In a large bowl, whisk together the melted butter and sugar until smooth and glossy. Add the eggs one at a time, whisking after each, then mix in the vanilla extract.
The mixture should look silky and a bit thick — that’s where the fudginess comes from.
Add the Dry Ingredients
In another bowl, mix together the flour, cocoa powder, salt, and baking powder. Gently fold the dry ingredients into the wet mixture until just combined.
Don’t overmix — it’s okay if there are a few streaks of flour left. Overmixing makes brownies cakey instead of chewy.
The batter will be rich and dark, thick but pourable.
Make the Peanut Butter Swirl
In a small bowl, mix the peanut butter with powdered sugar. It makes the texture thicker and easier to swirl without sinking into the batter.
Pour half of the brownie batter into a greased 8×8-inch pan lined with parchment paper. Spoon half of the peanut butter mixture over it, then add the rest of the brownie batter on top.
Drop the remaining peanut butter in small spoonfuls across the surface and use a butter knife to gently swirl it in figure-eight motions. Don’t overdo it — a few turns give the prettiest marbled look.
Bake Until Set
Bake at 350°F (175°C) for about 25–30 minutes, or until a toothpick inserted near the center comes out with moist crumbs (not completely clean).
Every oven is a little different, so check at 25 minutes and go from there. You want that dense, slightly gooey middle — not dry cake.
Let the brownies cool completely before slicing. I know it’s hard to wait, but it’s worth it. The texture settles as they cool, and the peanut butter swirl firms up beautifully.
Slice and Serve
Once cool, lift the brownies out using the parchment paper and cut into 12 squares. The edges will be chewy and crisp, the centers soft and rich.
They taste great on their own, but if you want to go all in, top them with a scoop of vanilla ice cream or drizzle with melted chocolate.
I usually make these on weekends, and somehow there are never leftovers. They’re that good.
Tips for the Best Peanut Butter Brownies
- Use creamy peanut butter. Natural peanut butter separates too easily and can make the swirl oily.
- Don’t overbake. Pull them out when they’re still slightly soft in the middle — they’ll firm up as they cool.
- Line the pan. It makes slicing so much easier and keeps the edges from sticking.
- Warm the knife. If you want clean cuts, dip your knife in hot water and wipe between slices.
- Let them rest overnight. If you can resist, they actually taste even better the next day.
Why I Love This Recipe
I think every home baker has that one recipe that feels like theirs. This is mine. It’s simple enough to make anytime, but it never fails to impress. The swirl always comes out a little different — sometimes bold, sometimes delicate — and that’s part of the fun.
It’s also the kind of recipe that brings people to the kitchen. The smell alone is enough to make everyone ask, “What’s in the oven?”
And honestly, there’s something comforting about making a dessert that feels both familiar and special. Chocolate and peanut butter never get old.
My blog also has other brownie variations, such as classic chocolate brownies and healthy sweet potato brownies.
Storing and Reheating
Keep the brownies in an airtight container at room temperature for up to 3 days, or in the fridge for a week.
To freeze, wrap individual pieces tightly in plastic wrap and store in a freezer bag. They’ll last up to two months. To enjoy later, warm one in the microwave for 10–15 seconds — it tastes freshly baked again.
Can I Use Natural Peanut Butter?
You can, but it behaves differently. Natural peanut butter tends to separate, which can make the swirl greasy. If you do use it, stir it very well and add a teaspoon of flour to stabilize it a bit before swirling.
Can I Make These Without Cocoa Powder?
If you’re out of cocoa powder, use melted dark chocolate instead. Replace the cocoa with 3 ounces of melted chocolate and reduce the butter slightly. The flavor will be deeper, and the brownies will be extra fudgy — just keep an eye on the bake time since they might need a few extra minutes.
