- Melt butter in a saucepan, stir in flour and cook a few minutes. Gradually add milk, stirring constantly. Bring to boil. Add mustard, salt, cayenne and cheese. Stir until cheese melts. Cool. Then stir in well beaten egg yolks. Beat egg whites until stiff. Fold into cheese mixture lightly. Pour into an ungreased souffle dish and
- bake in a slow oven (150C) for 50 - 60 minutes. Serve at once.