PREHEAT oven to 300°F. Melt butter in medium saucepan on medium-low heat. Stir in flour and seasonings. Gradually add milk, stirring until well blended. Cook until thickened, stirring constantly. Add cheese; cook until melted, stirring constantly. Remove from heat. Beat egg yolks lightly. Gradually add to cheese mixture, stirring until well blended. Cool slightly.
BEAT egg whites in small bowl with electric mixer on high speed until stiff peaks form. Add to cheese mixture; stir gently until well blended. Pour into 2-quart soufflé dish or casserole dish. With tip of spoon, make slight indentation or “track” around top of soufflé 1 inch from edge to form “top hat.”
BAKE 1 hour and 15 min. or until center is set and top is lightly browned. Serve immediately.