Butterfinger Brownies are fudgy and perfectly baked brownies topped with a sweet homemade Butterfinger frosting.
Preheat oven to 350°F. Prepare a 9x13-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.