Spinach Casserole

Directions

1. 1
   Make cream sauce with butter, flour and milk.
2. 2
   When smooth, add onion and cheese and stir until melted.
3. 3
   Add beaten egg yolks and spinach, then fold in stiffly beaten egg whites.
4. 4
   Pour into greased casserole and bake at 350° until knife inserted in center comes out clean.
5. 5
   Set casserole in pan of hot water to bake.
6. 6
   Bake 45 to 55 minutes.