This post teaches you how to make peanut butter swirl brownies in under 1 hour. Marbled with a thick, creamy peanut butter swirl mixture, these chocolate brownies are sheer perfection. They emerge from the oven moist, fudgy, and so satisfying. Ready? Let’s bake.
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Peanut Butter Swirl Brownies
These Peanut Butter Swirl Brownies are actually a recipe that I cut from my first cookbook, Even Better Brownies, at the last second and I'm SO excited to be sharing them with you guys today. If you're new here... brownie recipes made from scratch are kind of my thing. So whether you're looking for a classic chocolate brownie or a homemade brownie crinkle cookie, I've got you covered!
Now, back to these brownies! I’ve had peanut butter swirled brownies before... but none of them delivered that powerful and delicious chocolate & peanut butter punch that I was looking for. So, I decided to dive a little deeper… into the brownies that is, with literal chunks of peanut butter goodness. And boy do I think I've outdone myself this time. This recipe for brownies with a peanut butter swirl yields 16 brownies that deliver on all fronts: decadence, richness, chewiness, and of course, fudginess.
These chocolate peanut butter brownies don’t require a ton of ingredients; here’s what you’ll need to make them:
- Butter: The one and only. You'll need it for both the brownies and the peanut butter swirl.
- Cocoa powder: Because this recipe doesn't use any melted chocolate, I recommend using a Dutch-processed cocoa for that deep, chocolatey flavor although your regular unsweetened cocoa powder will work just fine!
- Espresso powder: This is different than instant coffee! Espresso powder further brings out the chocolate flavor; don’t worry… your brownies won’t taste like coffee, I promise!
- Sugar: This recipe uses both granulated and light brown sugar for the ideal fudge brownie texture that's not too sweet
- Vanilla: Leaving it out will result in brownies that taste a little bland. It's also used in the peanut butter swirl!
- Salt: Brownies made without salt taste a little plain, so don’t skip it. You'll also need just a pinch for the peanut butter swirl.
- Eggs: Three large (room temperature) eggs are all you need!
- All-purpose flour: Only 3/4 cup of all-purpose flour is needed!
- Baking powder: For just a little leavening action.
- Peanut butter: These are brownies with peanut butter after all...
How To Make Peanut Butter Swirl Brownies
These peanut butter swirl brownies are extremely simple to make and the results are unreal. Trust me! There are two essential components for this recipe: the brownie batter & the peanut butter swirl!
1. The Brownie Batter
The brownie layer contains your standard brownie ingredients; you know… butter, flour, eggs etc. This particular brownie recipe uses only cocoa powder which makes for a deliciously chewy brownie that comes together extremely quickly.
To assemble and bake the peanut butter swirl brownies, you’ll first line an 8×8 pan with parchment paper; this will help remove the brownies once they’re baked and have set. After the pan is lined with parchment paper, you’ll mix your brownie batter, and then mix your peanut butter swirl. Then you'll carefully drop alternating spoonfuls of each batter into your pan then swirl together with a butter knife and bake at 350°F (180°C) for 30-35 minutes, or until a toothpick comes out with moist crumbs. Then the hard part: letting the brownies cool completely before removing and slicing.
2. The Peanut Butter Swirl
This is the star of the show here. It’s simply powdered sugar, butter, vanilla, peanut butter, and salt mixed together to form a smooth paste-like filling that is dolloped over the brownie base before being swirled together. Yes please!
Serving & Storage
Serving: You can serve these brownies warm or at room temperature. They're best served within the first 3 days of being made. I like to reheat them a little in the microwave before eating!
Storage: Leftovers should be stored in an airtight container and can be kept at room temperature or in the refrigerator for up to 1 week. Leftovers can also be wrapped in plastic wrap surrounded by tin foil and then be frozen for up to 2 months.
Tips For Making Peanut Butter Swirl Brownies
- Use a commercial brand of peanut butter that is fully combined/emulsified. I don't recommend using “natural” peanut butter with oil separation.
- When swirling the peanut butter into the brownie batter, less is more. Thicker, more noticeable swirls come from less swirling. Drag a butter knife throughout the pan in a figure-8 motion, but don't overdo it!
- Do not overbake these; I can’t stress this enough! If you insert a toothpick into the center it should have moist fudgy crumbs on it, but no batter. As soon as that happens, pull them out and allow them to finish cooking/setting/cooling in the pan. Since all ovens bake differently, set your timer for about 5 minutes earlier than the recipe calls for and keep checking them every 2 minutes until they’re done.
Recipe Troubleshooting & FAQ
CAN I DOUBLE THIS PEANUT BUTTER SWIRL BROWNIE RECIPE?
Yes! You can easily double the recipe, and bake it in a 9×13-inch pan. You can adjust the ‘servings’ slider from 16 to 32 in the recipe card to get the proper ingredient measurements.
CAN I REDUCE THE SUGAR?
Unfortunately, no. It’s doing more than lending a sweet flavor. It’s actually helping with the overall structure and texture of the brownies.
HOW CAN YOU TELL WHEN THE BROWNIES ARE DONE BAKING?
A toothpick is your best friend when testing brownies for doneness. You’ll want to remove these brownies when your toothpick is covered in moist crumbs; they might even still look ever so slightly underdone in the center. The residual heat of the pan will continue to finish cooking them to fudgy perfection, however, so make sure to let them cool completely in the pan.
HELP! MY BROWNIES CAME OUT DRY. WHAT DID I DO WRONG?
If you used cup measures as opposed to weight measures, your ingredients were probably a little off. As weird as this sounds, measuring cups aren’t as accurate as you think. For example, somebody who scoops the measuring cup into the flour will have way more than somebody who uses a spoon to scoop the flour into the same sized measuring cup (and the person who spoons the flour into the measuring cup will probably still have more than the needed amount). This is why you should really be measuring by weight with a kitchen scale instead—it’s much more reliable and completely eliminates any inconsistencies.
Alternatively, if you measured your ingredients by weight and the brownies still came out too dry, you might have overmixed your brownie batter or overbaked the brownies. Overmixing the batter will allow air to get trapped in the batter and will result in dry, cakey brownies. Overbaking is pretty self-explanatory; make sure you remove the brownies when a toothpick inserted into the center comes out with moist crumbs sticking to it. If it comes out clean, you’ve probably overbaked them.
Now, get this recipe for brownies with a peanut butter swirl pinned, then let’s get baking, because, dude, these are SO DELICIOUS… you have to try them!
Peanut Butter Swirl Brownies
For the Brownies:
- 90 g all-purpose flour
- 200 g granulated sugar
- 110 g light brown sugar
- 40 g unsweetened natural or Dutch process cocoa powder
- ½ teaspoon fine sea salt
- ½ teaspoon baking powder
- 170 g unsalted butter melted
- 3 large eggs
- 1 teaspoon vanilla extract
For the Peanut Butter Swirl:
- 125 g creamy peanut butter
- 30 g unsalted butter melted
- 30 g powdered sugar
- 1 teaspoon vanilla extract
- ¼ teaspoon fine sea salt
- Preheat the oven to 350°F (180°C). Grease an 8×8–inch pan and line the pan with parchment paper, leaving an overhang on all sides.
- In a large bowl, whisk together the flour, granulated sugar, light brown sugar, cocoa powder, salt, and baking powder. In a medium bowl, add the butter, eggs, and vanilla and whisk until well combined. Add the wet ingredients to the dry ingredients and mix until just combined then set aside.
- In a small bowl, whisk together the peanut butter, butter, powdered sugar, vanilla, and salt until well combined.
- Drop large spoonfuls of the brownie batter randomly into the prepared pan. Top with random spoonfuls of all of the peanut butter batter. Drop random spoonfuls of the remaining chocolate batter over any bare or heavy peanut butter spots. Using a knife, swirl the batters together then bake for 30-35 minutes.
- Remove from the oven and place on a wire rack to cool completely in the pan before cutting into squares. Cover and store leftover brownies at room temperature for up to 1 week.
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