Preheat your oven to 350 degrees F (176 degrees C) and prepare a cupcake pan with cupcake liners.

In a large mixing bowl, combine sugar, brown sugar, butter, and peanut butter. Beat the mixture until it’s light and fluffy, about 3-4 minutes.

Add sour cream and vanilla extract to the bowl, mixing until everything is well combined.

Add the egg whites in two batches, mixing well after each addition.

In a separate bowl, whisk together flour, baking powder, and salt. In another small cup, combine milk and water.

Add half of the dry ingredients to the wet batter and mix well. Then add the milk mixture, followed by the remaining dry ingredients. Stir in the crushed Butterfingers.

Fill the cupcake liners halfway and bake for 18-20 minutes. Let them cool for 2-3 minutes, then transfer them to a cooling rack.

For the ganache: Microwave the heavy cream until it’s near boiling, then pour it over the chocolate chips. Cover, let sit for 3-4 minutes, then whisk until smooth.

For the frosting: Beat butter, peanut butter, and shortening until smooth. Gradually add powdered sugar, alternating with water/milk until you reach the desired consistency. Stir in the crushed Butterfinger.

Spread the ganache on top of the cooled cupcakes, pipe the frosting on top, and garnish with additional crushed Butterfinger and a piece of Butterfinger if desired.