For the filling, mix 1 cup of creamy peanut butter with 1/2 cup of powdered sugar until smooth. Fold in 1 cup of whipped topping or whipped cream to create a light and fluffy texture.
Spread a layer of softened vanilla ice cream over the frozen crust, about 1 1/2 to 2 inches thick. Freeze this layer until solid. Spread the peanut butter filling on top, creating an even layer, and freeze again until firm.
Warm 1/2 cup of caramel sauce and pour it over the peanut butter layer. Sprinkle with chopped peanuts to resemble the classic Snickers flavor. Freeze until the caramel hardens.
Make chocolate ganache by heating 1/2 cup of heavy cream and pouring it over 4 ounces of chopped dark chocolate. Stir until smooth and pour over the pie. Allow it to set in the freezer.
After adding the ganache, let the pie freeze for at least 2 hours or until fully set. This ensures the layers hold their shape when sliced.
To serve, remove the pie from the freezer and let it sit at room temperature for a few minutes to soften slightly. Cut into slices and serve with additional caramel sauce, if desired. Store in the freezer, covered, for up to a week.