2 qts. white stock, cold
2 egg whites, slightly beaten
2 crushed egg shells
4 tsp. water

In a large kettle, stir into the cold white stock, the egg whites and the egg shells mixed with the water. Slowly heat to a boil, stirring constantly. Remove from heat. Cool 25 minutes; strain through a colander covered with 2 layers of cheesecloth. Refrigerate until needed. Can be frozen.