If you are going to make the graham cracker crust, preheat the oven to 325F. Grease a mini muffin pan with cooking spray. In a large bowl, mix together the graham cracker crumbs, butter and sugar. Add about a tablespoon to each muffin cavity. Use the back of a small measuring spoon to pack in the mixture, leaving an indent in the middle. Bake for about 7 minutes, then let cool completely.