- Melt butter. Add flour and salt. Blend.
- Add milk. Cook stirring constantly until thick and smooth.
- Add shredded cheese. Stir until melted. Gradually add sauce to egg yolks.
- Carefully fold in egg whites beaten stiff but not dry. Pour in ungreased baking dish.
- Bake in pan of hot water in moderately slow oven. (325°) for 1 hour and 15 minutes, or until mixture doesn't adhere to knife.