HOW TO MAKE IT :
- Preheat oven to 350°F. Prepare a 9×13-inch baking dish with nonstick spray or GOOP.
- In a large bowl, add flour, cocoa, baking powder, and salt. Whisk together ingredients until they are fully incorporated.
- In the bowl of a stand mixer or in a large bowl using a hand-held mixer, beat the eggs, sugar, butter, and vanilla until light and fluffy.
- With the mixer off, add in the flour mixture. Turn the mixer on low and mix until ingredients are well combined.
- Pour brownies into the prepared baking dish and bake for 30-35 minutes. Brownies are done when an inserted toothpick is removed with crumbs but not wet batter. Let cool while you make the frosting.
- In the bowl of a stand mixer with the paddle attachment, combine the butter, sugar, Butterfingers, and salt.
- Start mixing on low speed until the sugar is incorporated with the butter. Increase the mixing speed to high and beat until smooth and fluffy, about 2 minutes.
- Adjust the consistency with milk as needed.
- Top the cooled brownies with the Butterfinger frosting. Serve.