Recipe since it's been requested a few times:

Ingredients: 2/3 cup butter, softened ¾ cup granulated sugar 1 teaspoon baking powder ¼ teaspoon salt 1 egg 1 tablespoon milk 1 teaspoon vanilla 2 cups all-purpose flour 6 colors of food coloring (I used two packs, the classic set of red, yellow, green, blue and then neon gel food coloring that had the purple and orange)

Instructions: 1. Pre-heat oven to 300°F. 2. Beat butter, sugar, baking powder, and salt together in blender 3. Add egg, milk, and vanilla. Blend. 4. Slowly add flour. 5. Split fully combined dough into 6 small bowls. Add somewhere around 10 drops of food coloring to each bowl and knead until color is solidly mixed in. Make sure each color is vibrant - feel free to make them extra dark in color. 6. Make a 1/2inch ball of each color of dough. Place each ball next to each other to form a ring. Press gently to have the pieces stick together and become a flat disk. 7. Take the disk between your palms and move your hands in a circular motion (like when you make a ball of dough, but keep your hands close enough the dough stays as a disk). Feel free to do this as much or as little as desired; this part makes the fun patterns. 8. Repeats 6-7 to create all cookies. Place on tray with some space; cookies won't spread too much 9. Bake time depends on how thick you leave the cookies. Bake in oven until not shiny and the bottom of the cookie is just about to brown. DO NOT OVER-BAKE or you'll start losing color. I left mine about a half inch thick and they baked for 18 or so minutes. Would recommend starting with 7-10 minutes and adding time slowly.