Preheat the oven to 350 degrees Fahrenheit. Line an 8x8 baking dish with foil or parchment paper, and set aside.
In a medium-sized pan over medium heat, melt the butter just until it has browned.
2 sticks unsalted butter
Remove the pan from the heat, and stir in the sugar until well combined.
1 1/2 cups light brown sugar
Add the eggs and vanilla, and whisk until smooth.
2 large eggs, 1 teaspoon vanilla extract
Stir in the flour, baking powder, and salt just until combined. Gently fold the Reese’s Pieces and chocolate chips into the batter.
2 cups organic all-purpose flour, 1 teaspoon baking powder, 1/2 teaspoon kosher salt, 1/2 cup semi-sweet chocolate chips, 1 cup Reese’s pieces
Pour half the batter into the prepared pan.
Heat the peanut butter in a microwave-safe dish in the microwave for 30 seconds to melt. Pour it over the blondie batter, and add the remaining batter on top.
1/2 cup smooth peanut butter
Bake 25-30 minutes or until the edges are firm and golden and the center is still soft.
Remove the baking dish from the oven, and immediately sprinkle the peanut butter cups on top.
12-16 Reese’s mini peanut butter cups
Set aside to cool and set. Slice into bars, and serve!
Store covered at room temperature for up to 1 week.