My boyfriend and I just started our own business. We bake our own dog treats, mainly low-fat treats with no sugar. Instead of using frosting (because it is made of sugar), after the cookies are cooled, paint the desired food coloring onto the cookie. While it's still wet, you can add sprinkles if desired and within minutes the food coloring will dry and there you go. I have noticed that the colder the dog treats, the more enjoyed they are.