Cook one 10-ounce package frozen chopped broccoli according to package directions. Drain very thoroughly (chop any large pieces). Add 2 tablespoons butter to broccoli. Cook and stir over high heat until butter is melted and any excess moisture has evaporated.

Blend in 2 tablespoons all-purpose flour and 1/2 teaspoon salt. Add 1/2 cup milk all at once. Cook and stir over medium heat until mixture thickens and bubbles. Remove from heat. Stir in 1/4 cup grated Parmesan cheese. Beat 4 egg yolks until thick and lemon colored. Slowly add broccoli to egg yolks, stirring constantly. Gradually pour over 4 stiffly beaten egg whites folding together thoroughly. Pour into ungreased 1-quart souffle dish.

Bake at 350 degrees for 35 minutes or until knife inserted halfway between center edge comes out clean. Serve immediately with mushroom sauce.

Makes 4-6 servings.