Preheat your oven to 350°F (175°C) and prepare your brownie mix in a 9x13-inch pan according to the package instructions. Bake for 25-30 minutes until a toothpick comes out with a few moist crumbs. Allow the brownies to cool completely in the pan for about 1 hour.

Using a sharp knife or a cake ring, carefully cut out two 6-inch circles from the cooled brownie slab. Keep the cut brownie circles intact for layering.

Place one brownie circle at the bottom of a 6-inch springform pan. Spread one pint of chosen softened ice cream evenly over the brownie layer.

Place the second brownie circle on top of the first ice cream layer. Spread the remaining pint of softened ice cream over the top brownie layer.

Cover the springform pan tightly with plastic wrap and freeze for at least 4 hours until the ice cream is firm.

Remove the cake from the freezer about 5 minutes before serving to soften slightly. Release the springform pan carefully.

Warm chocolate fudge sauce in the microwave until just liquid. Drizzle over the top of the cake and sprinkle leftover brownie pieces if desired.