Prep the Pan: Preheat oven to 350°F. Line a 9x13 baking dish with parchment paper and set aside.

Make the Brownie Batter: In a large microwave-safe mixing bowl, melt 1 cup unsalted butter completely. Add 2 cups granulated sugar, 1 cup unsweetened cocoa powder, 1 tablespoon pure vanilla extract, and 3 large eggs. Whisk until smooth and fully combined. Add 1 cup all-purpose flour, ½ teaspoon baking powder, and ½ teaspoon kosher salt. Whisk until just combined. Do not overmix. Fold in half of the chopped Butterfingers.

Bake: Pour the batter into the prepared dish and bake for 20–25 minutes, or until a toothpick comes out clean. Place the pan in the freezer to cool for about 15 minutes.

Prepare the Frosting: Finely chop the remaining Butterfinger candy bars (or pulse them in a food processor until pea-sized). In the bowl of a stand mixer fitted with the paddle attachment, combine 1 cup unsalted butter, 15- ounce jar honey roasted peanut butter, 4 cups powdered sugar, 1 tablespoon pure vanilla extract, and ½ teaspoon kosher salt. Beat on medium speed until smooth and creamy, about 3 minutes. Stir in candy bar crumbs on low, then beat on medium speed until fluffy. If the frosting is too thick, add 2 –4 tablespoons milk, 1 tablespoon at a time until it’s thick but spreadable.

Assemble the Brownies: Spread the frosting evenly over the cooled brownies. Pour melted 6 ounces milk chocolate chips over the top and spread with a spatula until smooth. Chop 1 large Butterfinger bar and sprinkle over the top for garnish.

Serve: Chill for 10–15 minutes for clean slices. Serve and enjoy!