Stir together molasses and brown sugar in a large mixing bowl. Stir in melted butter. Stir in flour, cinnamon, baking soda, ginger, cloves, pepper, mustard, and allspice until well combined. Divide dough in half. Cover and chill for 1 to 2 hours or until easy to handle.
Roll each portion of dough on a lightly floured surface until 1/16 inch thick. Cut with a floured 2-inch scalloped round cutter. Place on a greased cookie sheet. Bake in a 375 degree F oven for 5 to 6 minutes or until lightly browned. Transfer to wire racks to cool. Makes about 66.