Preheat oven to 300ºF.

To make a cheese sauce:
Melt butter over medium low heat. When melted add flour and mix well. Let this mixture cook for about 2 minutes, stirring constantly.

Add the milk slowly, whisking it in. Cook over medium low heat until it thickens. Add cayenne, Worcestershire, salt and cheese. Cook over low heat until cheese melts. Remove from heat and cool slightly.

Beat egg yolks well. Add to cheese mixture and blend thoroughly (make sure sauce has cooled a bit or eggs will cook).

Beat egg whites until stiff but not dry. Fold egg whites gently into cheese mixture. Pour into 2-quart soufflé dish or casserole with straight sides, running the tip of a spoon around the mixture one inch from the edge of the dish. This forms a box top lid on the soufflé.

Bake for 1 hour and 5 minutes.