- 2 tablespoons butter, melted
- 2 tablespoons flour
- 1 cup milk
- 1/2 teaspoon salt
- pinch of pepper
- 1 egg yolk, beaten
- 1 cup grated store cheese (1/4 pound)
Stir flour into melted butter, add salt, then add the milk slowly, stirring continuously. Add pepper and cook about 4 minutes over very low heat, stirring all the while to prevent lumping. Add cheese and keep hot over boiling water until cheese is melted and has blended with sauce. Just before serving, stir sauce into the beaten egg yolk and return to heat. Stir 1 minute, then serve.