Sacher Tafelspitz aspic with lamb's lettuce
Preheat oven to 150°C. Salt butter, mix with the egg yolks (mixer) until frothy, and milk and flour. Beat egg whites until they stand in soft peaks, fold into the butter-egg yolk mixture. Put the mixture onto a greased baking tin (or a baking tin covered with baking paper) as thick as a finger, bake in the oven for 12-15 minutes until golden. Allow the dough to cool off and then cut into rhombic pieces ("Schöberl").