Step 1

Set up your pan: Lay a sheet of parchment or wax paper on a baking sheet, and place your cold springform ring (without the bottom) on top.

Step 2

Whip the vanilla ice cream: Whip the vanilla ice cream with a mixer for about 2 minutes, or until fluffy but still frozen.

Step 3

Create the vanilla ice cream layer: Spread the whipped ice cream up the sides of the pan, creating a thick layer of vanilla all around. Spread the rest in the bottom, and smooth out. (A little ice cream may puddle out the bottom as it melts. This is fine; we'll take care of that later.)

Step 4

Add 2 cups crushed cookies: Spread a thick, even layer of cookies over the ice cream and lightly press in.

Step 5

Add 2 cups fudge sauce: Warm the fudge sauce just enough to make it easily pourable, but not too hot, then pour over the cookies.

Step 6

Freeze for 4 hours: Freeze for at least 4 hours, or overnight if you have the time.

Step 7

Create the chocolate ice cream layer: Whip the chocolate ice cream with a mixer until fluffy but still frozen. Spread on top of the cookie and fudge layer and smooth it so it's even with the top of the pan. Cover the top with another sheet of parchment or wax paper.

Step 8

Freeze overnight: Freeze overnight or until completely solid.

Step 9

Prep the cake for unmolding: Peel away the top layer of parchment or wax paper. Place a large round plate or platter over the top of springform pan, upside-down. Gently flip the whole cake over, so that it ends up on the plate with the chocolate layer on the bottom and the vanilla layer on top. Peel away the other piece of parchment. Trim away any frozen bits of ice cream on the outside of the cake.

Step 10

Unmold the ice cream cake: Gently loosen the springform and wiggle it until it slides smoothly off the cake. Dab the base gently to mop up any melted ice cream. Return to the freezer while you whip the cream.

Step 11

Frost with whipped cream: Whip the cream with the powdered sugar and vanilla until it forms soft peaks. Use an offset spatula to spread the whipped cream all over the cake. If desired, use a piping bag to create rosettes or other decorations.

Step 12

Decorate the cake: Add sprinkles, drizzles of Magic Shell, extra dollops of whipped cream, and Maraschino cherries, if desired.

Step 13

Freeze until eating: At this point, the cake can be eaten, but it will melt quickly. It's best to return it to the freezer, overnight if possible. It will also keep quite a while; once the cake and the frosting are firmly frozen, cover loosely with plastic wrap and freeze for up to 1 month.