Cook rice until tender.Rinse with hot and cold water.Make a sauce of butter,flour,and milk.Cook,until thickened.Beat egg yolks.Add rice,sauce,seasonings and cheese.Fold in stiffly beaten egg whites. Preheat oven to 350 degrees.Pour mixture into a greased shallow pan. Bake @ 350 degrees,35 to 40 minutes.Serves 6.