In a mixing bowl, cream together butter, sugar and Jell-O until well blended. Add eggs and cream well. Add salt, baking powder and flour, mixing well. At this point, for more intense color, add food coloring, a few drops at a time if desired. Scoop batter into a bowl, cover and refrigerate for 1-2 hours to harden. When ready to bake, pre-heat oven to 350 degrees. On a lightly floured surface, roll out dough 1/4 to 1/2 inch thick. Use cookie cutters to cut out patterns. Sprinkle with decorative sugar (the same color as the dough or contrasting color.) Line a baking sheet with parchment paper. Place cookies on baking sheet about 1 inch apart. Bake for 12-15 minutes or until done. Let cool on baking rack and then store in airtight container.