1. Crush 15 of the cookies into fine crumbs. Add the melted butter, then mix to combine. Press some of the crumbs into each cup of a 12-cup muffin pan. Set aside.
2. Break up 6 more of the cookies into chunks. Mix the softened ice cream with the broken-up cookies. Spoon some of the ice cream mixture into each cup of the muffin pan. Crush the remaining 2 to 3 cookies into crumbs and sprinkle over the cups.
3. Freeze until firm, then remove from the muffin pan and place in resealable plastic bags or other airtight containers.