Prepare your cake mix according to package directions.
Pour cake mix into 2 9 inch round pans sprayed liberally with nonstick spray.
Bake according to package directions.
Remove from oven and allow to cool completely.
Scoop ice cream into a large bowl and stir to soften.
Chop up your Butterfinger Cup minis into small pieces.
Stir your Butterfinger pieces into your ice cream.
Line a 9 inch springform pan with parchment paper.
Place 1 cake round into the bottom of your springform pan.
Spread half of your ice cream on top of the cake.
Place 2nd cake round on top of the ice cream.
Spread remaining ice cream on top of cake.
Place in freezer and allow to freeze for 6-8 hours.
Spread cool whip around sides and top of cake.
Drizzle with peanut butter and chocolate, if desired.
Place in freezer for another hour before serving.