Grease a 9 inch springform pan with cooking spray. Line the inside of the springform with parchment paper so that it extends 2-3 inches above the hight of the pan. Spread the softened chocolate ice cream on the bottom of the pan and freeze for at least 10 minutes.
Remove lid from the fudge sauce and microwave until it is pourable. Pour one jar of fudge sauce over the chocolate ice cream. Sprinkle on the Oreos and then pour the other jar of fudge sauce over the Oreos. Freeze for at least 30 minutes.
Spread the vanilla ice cream over the fudge layer and freeze for at least 2 hours. Remove from freezer and let sit at room temperature for 5 minutes before removing the springform. Put back in freezer.
Prepare the whipped cream: beat the whipped cream and sugar in a chilled bowl until stiff peaks form. Spread a thin layer on the cake and refreeze for 15 minutes. Apply a second thicker layer over the cake. If decorating, apply the sprinkles and other decorations now and freeze to harden.
Remove from freezer about 10 minutes before serving. Enjoy!
Notes
Make-Ahead Tip: You can make this entire cake up to 2 days in advance.