Peanut Butter Blondies with Chocolate Buttercream
Soft peanut butter bars covered with chocolate frosting— they’re incredibly indulgent!

Chocolate and peanut butter go together like, well, chocolate and peanut butter. It’s a combination that cannot be beat. And these peanut butter blondies with chocolate buttercream cannot be beat!
These blondies are a simple, no-fuss dessert, sure to please just about everyone. They’re perfect for parties, potlucks, and picnics! Just make sure you have a glass of milk nearby, you’ll need it to wash them down.

baking tip:How to cut brownies and bars cleanly
If you’re looking for pretty brownies and bar slices with clean edges, follow these tips!
- Prepare your baking pan with parchment paper with enough overhang on the sides to use as a handle to lift them out after baking.
- Let them cool completely to room temperature, which let’s them finish setting up. Bars hot from the oven are very soft and will make for messy slices.
- Remove bars from the pan using the parchment paper and transfer them to a cutting board.
- Use a large chef’s knife to slice the bars. Run it under hot water briefly to heat up the metal, then wipe dry before slicing. For the cleanest slices, heat and dry between each cut.
- (Optional) Use a ruler as a guide to make sure bars are cut to equal size.
You may enjoy these other peanut butter treats
- 4-Ingredient Peanut Butter Cookies
- Peanut Butter Swirl Brownies
- Peanut Butter and Jam Sweet Rolls
- Peanut Butter Caramel Cupcakes
- Chocolate Peanut Butter Cup Cookies

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This recipe was originally published October 2011.

Peanut Butter Blondies with Chocolate Buttercream
Ingredients
Peanut Butter Blondies:
- 10 tablespoons unsalted butter (166 grams)
- 2 cups light or dark brown sugar (425 grams)
- 1 cup peanut butter (270 grams), smooth or crunchy
- 2 large eggs
- 2 teaspoons vanilla extract
- ½ teaspoon salt
- 2 cups all-purpose flour (240 grams)
- 1 teaspoon baking powder
Chocolate Buttercream:
- 6 tablespoons unsalted butter (85 grams), softened to room temperature
- ¼ teaspoon salt
- 2 cups powdered sugar (227 grams), sifted
- 3-4 tablespoons milk
- ¾ cup semi-sweet or bittersweet chocolate chips (128 grams), melted
Instructions
To make the blondies:
- Preheat oven to 325°F. Line a 9x13 inch baking pan with parchment paper or grease with nonstick baking spray.
- Melt the butter and sugar together in a medium saucepan over medium heat. Once melted, remove from heat and allow to cool for 5 minutes. Stir in the peanut butter until combined. Add the eggs one at a time, and then the vanilla, stirring until combined.
- In a separate bowl, combine the flour, baking powder, and salt. Add to the wet ingredients and stir until combined. Spread the batter into the prepared baking sheet. Bake for 30-40 minutes, until a toothpick inserted into the center comes out mostly clean.
- Let cool completely before frosting.
To make the buttercream:
- Combine all ingredients in the bowl of a stand mixer fitted with a paddle attachment. Beat on medium speed until smooth, scraping down the mixer bowl a few times as needed.
- Frost blondies with buttercream. Slice into squares and serve.
Notes
- To melt chocolate, microwave chocolate in a heat-proof bowl on high in 30 second intervals. Stirring until smooth.
These blondies were so delicious! I’ll be making them again and again!