Check the sauce for seasoning and add more salt and pepper if needed. If you need a richer, more luxuriant, sauce beat in an egg yolk and 3 tablespoons of cream. For some purpose I added some parsley to the dish, although it doesn’t say so within the recipe. It is sort of homogenous with no gristly bits, so don’t fear. Now make a simple béchamel sauce by melting an oz of butter in a saucepan.