Line the bottom and sides of a 9-inch springform pan with plastic wrap, leaving enough overhang to assist in lifting later.

In a medium bowl, combine crushed Oreo cookies and melted butter until the texture resembles wet sand.

Press the cookie mixture firmly into the bottom of the prepared pan and freeze for 15 minutes to set.

Spread the softened chocolate ice cream evenly over the crust. Freeze for 45 minutes until the surface is firm.

Pour the chilled chocolate fudge sauce over the chocolate ice cream layer, spreading it to the edges. Freeze for 30 minutes.

Spread the softened vanilla ice cream over the fudge layer. Cover the pan with plastic wrap and freeze for at least 6 hours or overnight until completely solid.

In a large chilled bowl, whisk heavy cream, powdered sugar, and vanilla extract on high speed until stiff peaks form.

Release the springform pan sides and peel back the plastic wrap. Transfer the cake to a serving platter.

Frost the top and sides of the cake with the whipped cream and garnish with chocolate chips or sprinkles.

Freeze for an additional 1 hour before slicing. Dip a sharp knife in warm water between cuts for clean slices.