Preheat your oven to 325°F (160°C). Line a standard muffin pan with cupcake liners or grease the cups lightly with butter.
In a food processor or a large bowl, combine the graham cracker crumbs, sugar, and melted butter. Stir until the mixture has a damp, sandy texture.
Firmly press approximately 1 tablespoon of the crust mixture into the base of each muffin cup. use the back of a spoon or small glass to press the crust firmly into place.
Bake the crusts for 5 minutes until set, then remove from the oven and let them cool while you prepare the filling.