Add Oreo cookies to the bowl of a food processor and pulse until broken up into fine crumbs. If you don't have a food processor, you can use a blender or alternatively place the cookies in a zip-top bag and use a rolling pin to break them up into finely crushed crumbs. You need 1 ½ cups of crumbs.

Add melted butter and pulse until evenly coated (or add cookie crumbs to a bowl and mix with a rubber spatula).

Press buttered cookie crumbs into the bottom and up the sides of a pie plate or spring form pan. Use a flat-bottomed measuring cup or drinking glass to help press the crumbs in so that they're in a compact, even layer. Freeze until ready to fill.

Add the softened vanilla ice cream to a large bowl along with the chopped candy, then mix until evenly distributed. Transfer to the frozen pie crust, smooth out the top, then immediately place into the freezer (unwrapped).

Freeze for several hours (or overnight) until firm. Once the ice cream filling is frozen solid, you can wrap it tightly with plastic wrap. If you wrap it before the filling has frozen, the plastic wrap will stick to the filling.

To serve, run a sharp knife under hot water, then cut into thin slices. Run the knife under hot water before every slice to ensure it can cut through the frozen solid ice cream.