Put all ingredients except food coloring into a bowl and cut with pastry blender until ingredients are incorporated in pieces the size of small peas. Add food coloring or, for varied colors, spoon equal amounts of mixture into several small bowls and add 1 drop of food color into each. Stir and knead the dough in each bowl separately until creamy and smooth and of even color. You may want to do this on a table rather than in the bowls. Roll the dough into tiny balls, then dust with fine granulated sugar or powdered sugar. If desired, press into rubber or plastic molds; immediately remove and let dry overnight. These mints will remain soft.