These peanut butter brownies made from a boxed brownie mix and plain peanut butter swirls are quick, simple, and delicious. While boxed mixes make baking easy, these brownies feel homemade thanks to chunks of Reese’s peanut butter cups folded into the batter and warm peanut butter swirls on top. The result is a fudgy, attractive brownie that no one would guess started with a mix. Serve warm with ice cream for an extra-special treat. If you enjoy cake-mix-based desserts, try other favorites from the same collection.
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Reese’s Peanut Butter Swirl Brownies (made with brownie mix)
marilynpeight
15 minutes
30 minutes
Equipment
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13 by 9 inch baking dish
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Cutting board
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Mixing bowl
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Measuring cups
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Skewer or toothpick
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Spatula
Ingredients
- 1 18.3 oz. fudgy brownie mix (I used Duncan Hines)
- 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
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Combine the brownie mix with eggs, milk, and oil, stirring just until there are no dry lumps and the batter is moistened. Gently fold in the chunked Reese’s peanut butter cups.
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Spread the batter into a parchment-lined or greased 13 by 9 inch baking dish, smoothing it evenly.
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Microwave the peanut butter for about 30 seconds, watching closely until it softens and becomes slightly bubbly at the edges. Drop teaspoonfuls 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 peanut butter and create a swirl pattern.
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Bake for 25–30 minutes, or until a toothpick inserted in the center comes out mostly clean with a few moist crumbs. Cool before cutting, or serve warm with ice cream. Enjoy!
Notes
Lining the pan with parchment paper makes it much easier to lift the brownies out for cutting.
Step-by-step photos are included in the post to help guide you through the process.
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Equipment needed for these Reese’s Peanut Butter Swirled Brownies:
- 13 by 9 inch baking dish — a glass dish is helpful for checking doneness; lining with parchment paper makes removal easier.
- Cutting board — useful for chopping the Reese’s peanut butter cups.
- Mixing bowl — a medium bowl works well for this batch size.
- Measuring cups — for the oil, peanut butter, and candy.
- Skewer, toothpick, or dinner knife — for creating peanut butter swirls.
- Spatula — for spreading batter and scraping the bowl.
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Ingredients summary: Fudgy brownie mix, eggs, oil, milk (or water), creamy peanut butter, and Reese’s peanut butter cups.
About the milk:
Milk isn’t required — water will work — but milk adds richness, extra moisture, and a slightly better flavor. For the fudgiest result, use milk.
Step 1: Mix the brownie mix with eggs, milk, and oil until just combined, then fold in the chunked Reese’s peanut butter cups.
Substitutions for Reese’s:
If you don’t have Reese’s on hand, other chopped candies or chocolate chunks (Snickers, Hershey bars, Milky Way pieces, or similar) will work. Adjust to taste.
Step 2: Spread the batter into a parchment-lined or greased 13 by 9 inch pan.
Step 3: Melt the peanut butter briefly in the microwave, then drop spoonfuls over the batter and swirl with a skewer, toothpick, or knife to create a marbled effect.
No skewer? No problem:
A toothpick, dinner knife, or even the tip of a spoon works to make the swirls. Imperfect swirls still look and taste great.
Why plain peanut butter?
Plain creamy peanut butter balances the sweetness from the Reese’s cups and the brownie mix. Using sweetened peanut butter is optional but may make the dessert noticeably sweeter.
Step 4: Bake at 325°F for 25–30 minutes, until a toothpick comes out mostly clean. Cool before slicing or serve warm with ice cream.
Storage:
Store cooled brownies tightly wrapped at room temperature for several days, or freeze in an airtight container for longer storage. Thaw at room temperature before serving.
If you make these, feel free to pin the recipe and tag the creator on Instagram with a photo of your brownies. Thank you for your support!
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