Germans call this Koch Kaese, which
Mix the cheese with the seasonings, cover with plastic wrap and a lid, and put in a warm (70°) place.
Let it ferment 3 to 4 days, stirring once each day.
Warm the butter in the milk, stir in the cheese, and cook gently about 10 minutes. Put into a blender or food processor and blend until smooth. Add the egg yolk and blend again so that it will be slightly glossy. Scoop mixture into a bowl and cover with plastic. Refrigerate until needed. This will keep up to 2 weeks.
© 1986 Betty Fussell. All rights reserved.