Reese's Peanut Butter Swirl Brownies Recipe with Brownie Mix

These Reese’s Peanut Butter Swirl Brownies use a fudgy brownie mix and smooth peanut butter swirls for a quick, show-stopping dessert. Chunks of Reese’s peanut butter cups are folded into the batter and melted peanut butter is swirled on top—no confectioner’s sugar required. Serve warm with ice cream for an extra treat. This easy shortcut yields brownies that look and taste homemade, even though they start from a box mix.

Reese’s Peanut Butter Swirl Brownies (made with brownie mix)

marilynpeight

Chunks of Reese’s peanut butter cups are baked into a rich, fudgy brownie and finished with smooth peanut butter swirls. These brownies are easy to make and deliver impressive flavor and texture.

5 from 1 vote

Prep Time
15 mins

Cook Time
30 mins

Course
Dessert

Cuisine
American

Servings
12

Equipment

13 by 9 inch baking dish
Cutting board
Mixing bowl
Measuring cups
Skewer, toothpick, or knife for swirling
Spatula

Ingredients

1 18.3 oz. fudgy brownie mix
2 large eggs
1/2 cup vegetable or canola oil
3 tablespoons milk (see note)
1 cup Reese’s peanut butter cups, chunked
1/3 cup creamy peanut butter

Instructions

Preheat oven to 325°F

Combine the brownie mix with the eggs, milk, and oil. Stir just until the batter is moistened and mostly lump-free. Gently fold in the chunked Reese’s peanut butter cups so they are evenly distributed.
Spread the batter into a parchment-lined or greased 13 by 9 inch baking dish, smoothing the top with a spatula.
Microwave the creamy peanut butter about 20–30 seconds until pourable and slightly bubbly at the edges—watch closely to avoid overheating. Drop teaspoon-sized dollops of the melted peanut butter across the batter about 1–2 inches apart. Use a skewer, toothpick, or the tip of a knife to drag lines through the dollops, creating a swirled pattern.
Bake in the preheated oven for 25–30 minutes, or until a toothpick inserted in the center comes out mostly clean with a few moist crumbs. Cool in the pan, then lift out the parchment for easy slicing. Serve warm or at room temperature; warm brownies are lovely with vanilla ice cream.

Notes

Milk is optional—you can substitute water if needed. Milk adds extra richness and makes the brownies slightly more moist and fudgy.

Line the pan with parchment paper for easier removal and neater slices.

If you don’t have Reese’s cups, try other chocolate or peanut-butter candies chopped into similar-sized pieces to maintain texture and distribution.

Tried this recipe?
Let us know how it was in the comments!

Equipment needed for these Reese’s Peanut Butter Swirled Brownies:

13 by 9 inch baking dish — glass or metal; lining with parchment paper makes removal easy.
Cutting board — to chop the Reese’s peanut butter cups into chunks.
Mixing bowl — a medium bowl is ideal for this batch size.
Measuring cups — to measure oil, peanut butter, and candy pieces.
Skewer, toothpick, or knife — for making the peanut butter swirls.
Spatula — for spreading batter and scraping the bowl clean.

Ingredients needed for these Reese’s peanut butter swirled brownies: Fudgy brownie mix, eggs, oil, milk (optional), creamy peanut butter, and Reese’s peanut butter cups.

Is milk necessary?

Milk is not required—water works fine—but milk adds fat and flavor, producing a moister, richer brownie. If you prefer a slightly fudgier texture, use milk; otherwise, water will still yield a tasty result.

Step 1: Mix the brownie mix with eggs, milk (or water), and oil until just combined. Fold in chopped Reese’s cups.

Substitutes for Reese’s: If you don’t have Reese’s cups, chopped chocolate bars, chocolate chunks, Snickers, Milky Way pieces, or even chopped candy pieces can be used—choose a candy that complements peanut butter and chocolate.

Step 2: Spread batter into the prepared 13×9 pan.

Step 3: Melt peanut butter briefly until pourable. Dollop across the batter and swirl with a skewer or knife to create an attractive marbled top. You can make straight lines or random swirls—either looks great.

Tips if you don’t have a skewer: Use a toothpick, the tip of a dinner knife, or a chopstick. The goal is to pull the melted peanut butter through the batter to form streaks and marbling.

Step 4: Bake 25–30 minutes at 325°F until a toothpick comes out mostly clean. Cool, slice, and enjoy—warm with ice cream is a favorite serving option.

Storage:

Store brownies tightly wrapped at room temperature for several days. For longer storage, freeze in an airtight container for a few months and thaw before serving.

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