Beat 12 egg yolks with 1 glass fine sugar until white. Add the zest from 2 lemons, sprinkle on ¾ glass potato flour and ½ glass wheat flour, and mix every-thing thoroughly. Fold in 12 beaten egg whites, pour into a buttered paper casing or a tin form lined with buttered paper, and pop into the oven. For 24 persons, bake 1 layer from these proportions, and stack with a chocolate torte and a layer of marzipan.
For 6 persons, halve the ingredients.