Preheat oven to 375 degrees. Butter a 1 1/2-qt souffle dish and sprinkle 2 tbsp cheese over bottom and around the sides. Melt butter in a saucepan, add the flour and cook gently 2-3 min., stirring, until thick and smooth. Add milk and continue cooking over low heat 2-3 minutes. Add salt, cayenne pepper and rest of cheese. Sauce should be very thick. Beat 3 tbsp of hot cheese mix into egg yolk and return to saucepan, stirring 1 minute over low heat. Remove and pour in large bowl. Beat egg whites until stiff but not dry. Stir into cheese sauce. Spoon into souffle dish. Bake 35 min.
Herb souffle: Omit cheese, add 1 1/2 tbsp minced onion, 1 tsp basil, 1 tsp tarragon, and 1 tbsp parsley to cream sauce