These moist and fudgy peanut butter swirl brownies combine layers of peanut butter cookies with fudge brownies baked right on top, and finished with a swirl of peanut butter. They’re salty, sweet, nutty and fudgy, and if you love chocolate and peanut butter together, these are the perfect brownies for you!
You might also love this no churn chocolate peanut butter cookie ice cream, chocolate peanut butter cake, and salted peanut butter blondies.
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Why You’ll Love This Recipe
Chocolate + Peanut Butter. I love chocolate peanut butter cups, chocolate cake with peanut butter frosting, and pretty much anything else that combines chocolate with peanut butter. These peanut butter swirl brownies are a delicious mashup of deep, dark chocolate fudge brownies and nutty peanut butter cookies. And because I didn’t want to over-complicate the recipe, I used my simple 3-ingredient peanut butter cookies as the base, which comes together so fast.
Moist for Days. Because these are fudgy brownies, they stay moist for days after baking. You can also freeze them to enjoy later, and they’ll taste like they were freshly baked.
Standard Pantry Ingredients. You don’t need any complicated or hard-to-find ingredients for today’s recipe.
See the recipe card at the end of the post for the full ingredients list and instructions.
Ingredients
Peanut Butter Cookie
- Granulated Sugar. Sweetness.
- Peanut Butter. I suggest using creamy peanut butter, and you can use all-natural, or your favorite brand of peanut butter.
- Egg. Binds the cookie dough together. When making individual peanut butter cookies, I only use the egg yolk, rather than the whole egg. But for these peanut butter swirl brownies, you can use the whole egg for the peanut butter cookie base.
Brownies
- Unsalted Butter. Adds richness and keeps the brownies moist.
- Granulated Sugar. Sweetness, to balance the bitterness of the unsweetened cocoa powder.
- Chocolate Chips. Use dark or semi sweet chocolate chips. Melted into the brownie batter, the chocolate chips give the brownies a very fudgey texture, as well as contribute to the crackly top.
- Vanilla Extract. Flavor.
- Eggs. The eggs help to emulsify the batter, providing structure and leavening.
- Cocoa Powder. Use a good quality Dutch-processed cocoa powder.
- All-Purpose Flour. Gives the batter structure and strength.
- Salt. Balances the sweetness and enhances the flavor of the chocolate.
- Creamy Peanut Butter. For swirling on top of the brownie batter.
Instructions
Peanut Butter Cookie Layer
- Preheat the oven to 325 F. Line an 8×8 inch baking pan with parchment paper.
- In a bowl, stir together the sugar, egg and peanut butter until smooth and well combined.
- Spread the peanut butter cookie dough into the prepared baking pan, and bake for 20 minutes.
- The cookie base will be slightly puffed, but will not be fully cooked through. Set aside until you’re ready to add the brownie layer.
Brownie Layer
- Meanwhile, make the brownie batter. In a large saucepan, melt the butter and sugar over medium heat. Once it begins to bubble hard enough that you can’t stir down the bubbles, cook for two minutes. If you have an instant read digital thermometer, check the temperature. You want the butter and sugar mixture to reach between between 230-235 degrees Fahrenheit, which will help get the shiny crackly top on the brownies.
- Remove from the heat and use a wooden spoon to stir in the chocolate chips and vanilla until melted; the mixture will be grainy. Let cool for 10 minutes.
- Beat in the eggs, one at a time, until the mixture comes together into a smooth batter.
- In a bowl, sift together the cocoa powder, flour and salt. Add the dry ingredients to the batter and mix just until no dry streaks remain. The batter will be thick but spreadable.
- Gently spread the brownie batter over the hot peanut butter cookie layer. Add small dollops of peanut butter on top of the brownie batter and use a toothpick to create swirls in the brownies.
- Bake on the center oven rack for exactly 30 minutes. The brownies will be crackled on top and slightly puffed.
- Cool the brownies completely before cutting into squares, at least 4-5 hours, or overnight. It’s normal for the center of the brownies to settle and sink down as they cool. Because these peanut butter swirl brownies do take a while to cool and fully set, I like to bake them in the evening, cool for several hours, then cover with plastic wrap to finish cooling overnight before cutting them the next day.
- Lift the cooled brownies out of the pan by the parchment paper onto a cutting board to cut them into squares. Use a damp cloth to wipe your knife clean in between cuts for neat, clean edges on your brownies.
Be sure to read all of my BAKING FAQs where I discuss ingredients, substitutions and common baking questions, so that you can be successful in your own baking!
Frequently Asked Questions
What kind of cocoa powder do you use?
For today’s recipe, I used Rodelle Dutch Processed Cocoa Powder.
What kind of peanut butter do you use?
For every day eating, I use Adams 100% Natural Creamy Peanut butter. You can use natural peanut butter for the cookies, or you can just use your favorite brand.
Will this recipe also work in a 9 inch pan?
Yes, you can use a 9 inch pan instead of 8 inch, and your bars will be slightly thinner.
How should I store the leftover brownies?
Store these brownies in an airtight container at room temperature for up to 3 days. You can also freeze the brownies for up to 3-6 months, then thaw at room temperature.
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Peanut Butter Swirl Fudge Brownies
All recipes on Curly Girl Kitchen are developed for high altitude at 5,280 feet. See FAQs for adjusting to higher or lower elevations.
Ingredients
Peanut Butter Cookie
- 1 cup granulated sugar
- 1 large egg
- 1 cup creamy peanut butter
Brownies
- ½ cup unsalted butter
- 1 cup granulated sugar
- ½ cup dark or semi-sweet chocolate chips
- 2 tsp vanilla extract
- 2 large eggs
- ⅔ cup unsweetened cocoa powder (preferably Dutch-processed)
- ⅓ cup all-purpose flour, spooned and leveled
- ¼ tsp coarse Kosher salt (if using table salt, use half the amount)
- 2 tbsp creamy peanut butter, for swirling on top
Instructions
Peanut Butter Cookie Layer
- Preheat the oven to 325 F. Line an 8×8 inch baking pan with parchment paper.
- In a bowl, stir together the sugar, egg and peanut butter until smooth and well combined.
- Spread the peanut butter cookie dough into the prepared baking pan, and bake for 20 minutes. The cookie base will be slightly puffed, but will not be fully cooked through. Set aside until you're ready to add the brownie layer.
Brownie Layer
- Meanwhile, make the brownie batter. In a large saucepan, melt the butter and sugar over medium heat. Once it begins to bubble hard enough that you can't stir down the bubbles, cook for two minutes.TIP: If you have an instant read digital thermometer, check the temperature. You want the butter and sugar mixture to reach between between 230-235 degrees Fahrenheit, which will help get the shiny crackly top on the brownies.
- Remove from the heat and use a wooden spoon to stir in the chocolate chips and vanilla until melted; the mixture will be grainy. Let cool for 10 minutes.
- Beat in the eggs, one at a time, until the mixture comes together into a smooth batter.
- In a bowl, sift together the cocoa powder, flour and salt. Add the dry ingredients to the batter and mix just until no dry streaks remain. The batter will be thick but spreadable.
- Gently spread the brownie batter over the hot peanut butter cookie layer. Add small dollops of peanut butter on top of the brownie batter and use a toothpick to create swirls in the brownies.
- Bake on the center oven rack for exactly 30 minutes. The brownies will be crackled on top and slightly puffed.
- Cool the brownies completely before cutting into squares, at least 4-5 hours, or overnight. It's normal for the center of the brownies to settle and sink down as they cool. Because they do take a while to cool and fully set, I like to bake them in the evening, cool for several hours, then cover with plastic wrap to finish cooling overnight before cutting them the next day.
- Lift the cooled brownies out of the pan by the parchment paper onto a cutting board to cut them into servings. Use a damp cloth to wipe your knife clean in between cuts for neat, clean edges on your brownies.
Brownies are fudgey and dense, and it has just the right amount of PB. Will make again.