These extra-fudgy chocolate brownies with peanut butter cups are swirled with a creamy peanut butter filling. They come together in about 20 minutes (no mixer required) and bake into super chewy, fudgy squares with a crackly top and pockets of chopped mini peanut butter cups.
Originally published May 2021; updated with new images.
Why you’ll love this recipe!
- Super chocolatey: The brownies use both chopped chocolate and cocoa powder for an intense chocolate flavor.
- Fudgy texture: No baking powder or baking soda means chewy, dense brownies rather than cakey ones.
- Peanut butter swirl: A simple peanut butter filling is swirled into the batter and topped with chopped mini peanut butter cups for extra indulgence.
- Crackly top: A glossy, crinkled top forms when the batter is mixed correctly—my favorite part.
- No mixer needed: These come together quickly by hand in about 20 minutes before baking.
Ingredients Needed
- Chocolate: The recipe uses both chopped dark chocolate and cocoa powder for depth.
- Flour: All-purpose flour is used here.
- Cocoa powder: Dutch-process is recommended for a richer flavor, but natural cocoa works if that’s what you have.
- Butter: Unsalted butter; European-style butter will give a slightly creamier result.
- Oil: A neutral oil (vegetable or similar) helps keep the brownies tender.
- Espresso powder: A small amount enhances the chocolate flavor without adding a coffee taste.
- Mini peanut butter cups: Chop them and fold most into the batter, reserving a handful to sprinkle on top.
- Peanut butter: Use creamy, conventional peanut butter (not natural with separated oil) for the filling.
Step-by-step instructions
Step One: Preheat your oven to 350°F (175–180°C). Grease and line an 8×8-inch square pan with parchment paper.
Step Two: In a small bowl whisk the flour with the salt and set aside. In a medium bowl or large jug, whisk together the eggs, egg yolk, light brown sugar, granulated sugar, oil, espresso powder and vanilla until smooth. Whisk for at least a minute to help develop the glossy top.
Step Three: Melt the butter and chopped dark chocolate together—either over a double boiler or in short bursts in the microwave—stirring until completely smooth. Add the cocoa powder and whisk until combined.
Step Four: Pour the egg and sugar mixture into the chocolate mixture and whisk until fully combined. Fold in the flour mixture gently until no dry streaks remain. Fold in most of the chopped mini peanut butter cups, reserving a small handful for the top.
Step Five: Make the peanut butter filling by briefly microwaving the creamy peanut butter until loosened, then stir in the powdered sugar, vanilla and a pinch of salt until smooth.
Step Six: Spread the brownie batter into the prepared pan. Dollop the peanut butter filling evenly over the batter, then use a butter knife to create swirls—be careful not to over-swirl or the pockets will disappear. Sprinkle the reserved chopped peanut butter cups on top.
Bake at 350°F (175–180°C) for 25–30 minutes. The top should be crackled and a toothpick inserted into the center should come out with a few moist crumbs. Let the brownies cool completely in the pan on a wire rack before lifting them out and cutting.
Expert tips & tricks
- Don’t overbake: Slightly underbaking yields fudgy brownies; they continue to set as they cool.
- Swirl gently: Use a butter knife to create visible peanut butter ribbons—too much swirling will blend them in.
- Cool fully: Cooling completely before slicing ensures clean edges and intact swirls.
Recipe FAQs
A light-colored metal pan is ideal. Dark pans can cause the edges and bottom to bake faster, producing drier brownies.
Grease the pan and create a parchment paper sling so you can lift the cooled brownies out easily.
Yes. Double the ingredients and bake in a 9×13-inch pan; adjust the baking time until a toothpick shows a few moist crumbs.
Store in an airtight container at room temperature for up to 3 days, or refrigerate for up to 5 days.
Try these next!
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Easy Raspberry White Chocolate Blondies
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Marbled Cheesecake Brownies
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Banana Cake with Chocolate Frosting
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Marble Loaf Cake
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Recipe
Brownies with Peanut Butter Cups
Equipment
- 8″ square pan
Ingredients
Brownies
- 2 eggs, room temperature
- 1 egg yolk, room temperature
- 3/4 tsp vanilla extract
- 5 1/2 oz (160 g) unsalted butter
- 1/4 cup (20 g) cocoa powder (Dutch-process recommended)
- 1/2 cup (72 g) all-purpose flour
- 4 oz (113 g) dark chocolate, chopped
- 1 tsp kosher salt
- 1/2 cup (100 g) light brown sugar
- 1/2 cup (100 g) granulated sugar
- 1/4 cup (60 ml) vegetable oil
- 1/4 tsp espresso powder
- 1 cup (160 g) mini peanut butter cups, chopped
Peanut Butter Filling
- 1/2 cup (134 g) creamy peanut butter
- 2 tbsp (20 g) powdered sugar
- 1/4 tsp vanilla extract
- Pinch kosher salt
Weigh ingredients with a kitchen scale for best results.
Instructions
- Preheat the oven to 350°F/180°C. Grease an 8×8 pan and line it with parchment paper.
- Whisk together the flour and salt in a small bowl and set aside.
- In a large jug, whisk the eggs, egg yolk, both sugars, oil, espresso powder and vanilla until combined.
- Melt the butter and chopped chocolate together over low heat (double boiler) or in the microwave, stirring until smooth.
- Add the cocoa powder to the melted chocolate and whisk until smooth.
- Pour the egg mixture into the chocolate and whisk until combined.
- Fold in the flour mixture, then fold in most of the chopped peanut butter cups; reserve a small handful for the top.
- In a medium bowl, warm the peanut butter briefly, then whisk together the peanut butter, powdered sugar, salt and vanilla until smooth.
- Spread the brownie batter into the prepared tin. Dollop the peanut butter filling across the top and use a butter knife to create swirls.
- Sprinkle the reserved chopped peanut butter cups over the top and bake 25–30 minutes, until the top is crackled and a toothpick has a few moist crumbs.
- Transfer to a wire rack and cool completely before lifting from the pan and slicing.
Notes
Peanut butter: Use creamy, conventional peanut butter rather than natural varieties with separated oil.
Butter: European-style butter is used here for a richer result, but regular unsalted butter works fine.
Salt: If using fine salt instead of kosher, halve the amount (1 tsp kosher = 1/2 tsp fine salt with Diamond Crystal as reference).
Storage: Store in an airtight container at room temperature up to 3 days, or refrigerate up to 5 days.
Nutritional information
The provided nutritional information is an estimate per serving. Accuracy is not guaranteed.
Leave a comment below and share how your brownies turned out!