Preheat the oven to 300 degree F. Grind the cookies in a food processor. If you don't have a food processor, place them in a zip bag and roll them with a rolling pin.
Mix in the butter, sugar and salt. Spray a muffin tin with non-stick spray. Scoop about 2 tablespoons of the mixture into each cup. Use a small cup to press each scoop of mixture, shaping it into a tiny cup.
Bake the cups for 12-15 minutes. Allow them to cool, then lift them out with your fingers or a small knife.
NOTES: This recipe is especially good with vanilla bean, lemon curd, or peach ice cream!