1. Put ice cream in the refrigerator 2-3 hours prior to assembling the ice cream cake. This will make the ice cream easier to spread. Mix and bake cake in a square baking dish according to package directions. Let cool on a wire rack before slicing.
2. In a large bowl, add whipping cream, powdered sugar free sweetener and unsweetened cocoa powder or Cacao Bliss. Beat on medium speed until frothy. Then increase speed to high and continue beating until stiff peaks form.
8. Add a final layer of whipped topping to the top and around the sides of the cake. Freeze for 10-20 more minutes to set the cake before slicing and serving.