Instructions

• Preheat oven to 350°F. Lightly grease a 9×13-inch pan with baking spray and line it with parchment paper, leaving an overhang on two sides to lift the blondies out later; set the prepared pan aside.
• Melt 1 cup unsalted butter and let it cool slightly until it is close to room temperature.
• In a large bowl, use a hand mixer to beat the melted butter with 1 cup white granulated sugar and 1 cup brown sugar until combined.
• Whisk in 3/4 cup creamy peanut butter, 2 large eggs, 1 egg yolk, and 1 Tablespoon pure vanilla extract until the mixture is fully combined.
• Using a spatula, fold in 2 cups all-purpose flour, 1 teaspoon baking powder, and 1 teaspoon salt until just combined; the batter will be very thick.
• Fold in 1 cup Reese’s Pieces and 1 cup mini peanut butter cups, reserving a small handful of Reese’s Pieces or mini cups if you want to sprinkle some on top.
• Transfer the batter to the prepared pan and spread it evenly. If you reserved any candy, sprinkle it evenly over the top.
• Bake for 30 minutes, then insert a toothpick into the center. If the toothpick comes out with wet batter, continue baking and check every 3 minutes. The blondies are done when the toothpick comes out with only a few moist crumbs—do not overbake.
• Remove the pan from the oven and place it on a wire rack to cool completely in the pan.
• Once cooled, lift the blondies from the pan using the parchment overhang, cut into bars, and serve.
• Store leftovers in an airtight container at room temperature for up to 1 week.