Erin’s Recipe Rundown
These easy gluten-free brownies start with a boxed mix but taste anything but basic, thanks to a generous peanut butter swirl and a rich, fudgy crumb. They’re my go-to when I want a quick dessert that pleases a crowd, without the work of baking from scratch!
Why You’ll Love Them: These brownies are deeply chocolately, with just the right amount of peanut butter swirled through. They come together in one bowl and always bake up perfectly—ideal for spontaneous dessert cravings!
Top Tips: Don’t overbake! Remove from the oven while the center still has moist crumbs to keep them fudgy. Slightly warm the peanut butter before adding so it spreads easily.
For more brownie recipes, try the best gluten-free brownies, gluten-free peanut butter brownies, gluten-free mint brownies, and chewy gluten-free brownies.
xoxo erin
This post was created in partnership with King Arthur Baking Company.
Ingredients You’ll Need
Here are a few notes on some of the key ingredients to make gluten-free peanut butter brownies. Jump to the recipe card below for the exact measurements.
Gluten-free cake mix: I like using King Arthur Gluten-Free Fudge Brownie Mix because it bakes up consistently fudgy, not dry or crumbly like some gluten-free mixes can be!
Peanut butter: Creamy peanut butter works best for smooth, clean swirls. Warm the peanut butter in the microwave for a few seconds so it drizzles and swirls easily without pulling up the batter. For a nut-free version, use sunflower seed butter.
Chocolate chips: Use semi-sweet or dark chocolate chips here—whichever you prefer! For dairy-free, use dairy-free chocolate chips.
How to Make Gluten-Free Peanut Butter Brownies
Here’s an overview of how to make this recipe. You can jump to the recipe for the full instructions!
Whisk the eggs and liquids: Combine the melted butter, water, and eggs, whisking until smooth and glossy.
Add the brownie mix: Pour in the gluten-free brownie mix and chocolate chips.
Mix: Gently stir until it comes together. It will be thick and fudgy—don’t overmix!
Add the peanut butter dollops: Spread the batter evenly in your greased, parchment-lined pan. Warm peanut butter for a few seconds in the microwave, then drop 9-10 small spoonfuls evenly over the top of the batter.
Swirl peanut butter: Use a toothpick or the tip of a knife to gently swirl in the peanut butter. Try to create pretty ribbons without mixing it completely into the chocolate. (Aim for a marbled effect.)
Bake: Bake until a toothpick comes out with moist crumbs but no raw batter. The center should jiggle slightly—that’s what keeps it fudgy. Cool at least 15 minutes before cutting.
Gluten-Free Box-Mix Peanut Butter Brownies
Ingredients
- 1 box King Arthur Flour Gluten-Free Fudge Brownie Mix
- 1/2 cup butter melted
- 2 tablespoons water
- 2 large eggs
- 1 cup chocolate chips
- 1/3 cup peanut butter
Instructions
- Preheat oven to 350°F (325° if using a glass or dark metal pan). Grease an 8" square or 9" round pan and line with parchment.
- Whisk together melted butter, water, and eggs. Stir in mix. Add chocolate chips. Spread batter evenly in greased pan.
- Drop spoonfuls of peanut butter on top of the batter, scattering evenly. (Warm peanut butter for a few minutes in the microwave beforehand if it's thick.) Then use a toothpick to swirl peanut butter.
- Bake for 35-40 minutes if using a light metal pan, or 35-35 if using a dark metal pan or glass pan. When brownies are done, a toothpick inserted in the center will have moist crumbs but no raw batter. Cool at least 15 minutes before cutting.
Notes
Dairy-Free: Use dairy-free butter and dairy-free chocolate chips.
Nut-Free: Omit peanut butter or substitute with sunflower seed butter.
To Make-Ahead: Brownies can be made up to 2 days in advance. Let them cool completely, then store in an airtight container at room temperature until ready to serve.
To Store: Store brownies in an airtight container at room temperature for up to three days.
To Freeze: Once baked and cooled, cut brownies into squares and freeze in a freezer-safe container or bag for up to 2 months. Thaw at room temperature before serving.
