Take your ice cream out of the freezer and allow to soften while you prepare the crust.
Add 20 oreos to your food processor and process on high until oreos are finely crushed. Add melted butter and pulse 20-30 seconds. Use a rubber spatula to spread cookie mixture to the bottom of an 8x8 inch pan.
When ice cream is soft enough to scoop easily, scoop half of the carton onto the cookie crust and spread into a flat layer.* Pour room temperature caramel sauce onto the ice cream layer, reserving about 2 tablespoons and set aside for later. Put pan in the freezer and allow to chill about 20 minutes.
In a bowl, mix together whipped topping and powdered sugar. Remove pan from freezer and spread whipped topping mixture on top of the caramel layer. Roughly chop the remaining oreos and sprinkle on top of the whipped cream layer. Drizzle remaining caramel sauce. Freeze at least 2 hours Cut into squares and serve cold.
This step is kind of tricky, but as you work with the ice cream it will get easier.