Gluten-Free Peanut Butter Cup Swirl Brownies

Celiac.com 11/18/2025 - Brownies began charming home bakers in the early twentieth century as a happy accident between cake and cookie—dense, fudgy, and unapologetically chocolate. Over the decades, bakers kept tweaking the formula, discovering that a glossy top and soft center come from melted chocolate, whisked eggs, and just enough flour to hold everything together.

Peanut butter cups arrived later as a candy-counter legend and quickly became a natural partner for chocolate desserts. This recipe brings the two together in a gluten-free format that still feels classic: a certified gluten-free oat-flour batter for gentle chew, bold cocoa and melted chocolate for depth, wide ribbons of warm peanut butter, and a shower of chopped peanut butter cups on top.

Ingredients

• 4 oz dark chocolate (60–70%), chopped
• ½ cup unsalted butter (or refined coconut oil)
• ¾ cup packed brown sugar
• ¼ cup granulated sugar
• 2 large eggs, at room temperature
• 1 teaspoon pure vanilla extract
• ½ cup unsweetened cocoa powder
• ⅔ cup certified gluten-free oat flour
• ¼ teaspoon fine salt
• ⅓ cup creamy peanut butter, warmed until pourable
• ½ cup chopped gluten-free peanut butter cups (plus extra for topping, optional)
• Flaky sea salt, for finishing (optional)

Instructions

1. Preheat the oven to 350°F (175°C). Line an 8-inch square pan with parchment, leaving overhang on two sides for easy lifting. Lightly grease the parchment.
2. Set a heatproof bowl over a pot of gently simmering water. Melt the chopped chocolate with the butter, stirring until smooth. Remove from heat and cool for 3–4 minutes.
3. Whisk in the brown sugar and granulated sugar until glossy. Add the eggs one at a time, whisking well after each, then stir in the vanilla.
4. Sift the cocoa over the bowl. Add the oat flour and salt. Switch to a spatula and fold just until no dry spots remain.
5. Fold in the chopped peanut butter cups. Scrape the batter into the prepared pan and smooth the top.
6. Warm the peanut butter until fluid (10–15 seconds in the microwave works). Dollop it over the batter in 5–6 spoonfuls, then drag a knife or skewer through to create wide swirls without overmixing.
7. Bake for 22–28 minutes, until the edges are set and the center tests with a toothpick that comes out with moist, fudgy crumbs (not wet batter). If desired, scatter a few extra chopped peanut butter cups on top during the last 3 minutes of baking to set them lightly.
8. Cool in the pan on a rack for at least 45 minutes. Lift out with the parchment and, for the cleanest slices, chill for 20 minutes before cutting. Finish with a pinch of flaky sea salt, if using.

Baker’s Notes

• Oat flour: Use certified gluten-free oat flour to avoid cross-contact. If grinding your own, blitz certified gluten-free rolled oats into a fine powder and measure after grinding.
• Texture control: For extra fudgy brownies, pull on the earlier side of the time range; for a chewier edge, add 2–3 minutes.
• Dairy-free option: Use coconut oil in place of butter and check that your chocolate and peanut butter cups are dairy-free and gluten-free.
• Shiny tops: Whisk the sugars into the warm chocolate mixture and beat in the eggs vigorously to encourage that crackly crust.

Serving and Storage

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Serve at room temperature, slightly warm, or chilled (the swirl tastes like fudge straight from the fridge). Store airtight at room temperature up to 2 days or refrigerate up to 5 days. For longer storage, wrap tightly and freeze for up to 1 month.

Conclusion

These Peanut Butter Cup Swirl Brownies celebrate everything people love about the classic bar—deep chocolate flavor, fudgy center, and a shiny top—while the gluten-free oat flour adds gentle chew and a wholesome note. The peanut butter ribbons and candy-cup crunch bring playful contrast in every bite. It is a bake-sale favorite that happens to be gluten-free, and a weeknight indulgence that tastes like a celebration.