For the white wine sauce:
- 60 ml (1/4 cup) of butter
- 60 ml (1/4 cup) of flour
- 80 ml (1/3 cup) of white wine
- 325 ml (1 1/3 cup) of milk
- 80 ml (1/3 cup) of cooking cream
- 80 ml (1/3 cup) of grated Gruyère cheese
- 10 ml (2 teaspoons) of lemon juice
- 1 pinch of finely grated nutmeg