Do not double this recipe.
In a large (at least 4 1/2 quart) bowl, beat eggs very light. Gradually beat in sugar, keep on beating, by hand one hour, one-half hour by mixer. Mix baking powder with flour, gently mix that in by hand. Make a stiff dough. Let it rest two hours in the refrigerator.
Grease three cookie trays and sprinkle with anise seeds. The anise seeds give the cookies their flavor. Roll out small portions to about 1/2 inch thick on a well-floured board. Dust the Springerle mold with flour and press it into the dough. Cut out with a sharp knife and set on cookie sheet. You will need to clean your knife off occasionally as it gets sticky Let cookies stand, covered with a clean cloth, at least 24 hours.
The next day: Bake in a 350 degree oven one tin at a time until white on top, about 10 to 15 minutes.
Notes: Molds are available through The House on the Hill and in cooking supply stores (in Philadelphia, try Fante's or Kitchen Kapers). Flat molds are easier than the rolling pin molds. The rolling pin molds distort the dough and the picture. Older molds and imported molds have better, sharper pictures. The House on the Hill also sells Hartshorn, pre-made dough, and flavorings.
Hartshorn is the traditional leavening. It is an ammonia compound and not harmful after baking. However, you can't eat the raw dough and the kitchen will stink of ammonia while the cookies bake.
Make sure your mixer is up to the job of these cookies. I burned out the motor on my mother's Sunbeam the first year I made these on my own. Faced with a dearth of springerle at Christmas -- or beating the batter by hand, my husband bought me a new mixer for Thanksgiving.