Still hunting for my recipe from Freiburg I just got some lovely lemon springerles from Alice at the Springerle Bakery: http://thatcookie.com/ where you can also get a recipe from Ken at http://cookiemolds.wordpress.com/recipes/springerle/ which uses baker's ammonia or Hartshorn for leavening. Ken likes to paint his springerles with petal dust finished with vodka for some gorgeous vivid results, but I am suggesting that you use all natural colorants such as those from India Tree with some thinning, either with water or German schnapps. I am uploading my results painting the cookies from Springerle, which are delicious and so perfect, they are well worth ordering! I will be making my own cookies with my own molds over the holidays. If you are going to make your own and they are intended for decoration, you can make a small hole in the top of each cookie so a ribbon can be inserted later for hanging. You can also try a wedgewood effect by simply painting the background a solid tanzanite blue or olive green and leave the border and central image white. You can box your painted edible cookies as gifts. I like to make these completely edible. Painting these would be great fun to do with children, too. House on the Hill has a great line of food coloring as markers which would be really easy for children to use. They also have edible gold dust you can paint with spirits for gilding. —Sagegreen
On a white porcelain plate squeeze out your three primary colors. Begin to mix two of each together to create your secondary colors.
Continue to mix your colors until you achieve the hues you want. Then with very fine paint brushes dip into the colors. Think of tinting the surface of the cookies with a range of hues.
Blend your colors further by dipping in and using a tiny amount of schnapps in your colors before painting on the cookies. Keep your brush relatively dry while working, so you do not saturate the surface of the cookie with moisture. If you do not like the results, very carefully and gently thin the color, blot with paper towel, and begin again. Let finished results dry thoroughly and store in an airtight container.