Beef Tenderloin Deluxe

1 (3- to 4-pound) beef tenderloin

1/2 cup chopped onion

1 1/2 tablespoons butter or margarine, melted

1 cup dry sherry

3 tablespoons soy sauce

2 teaspoons dry mustard

1/8 teaspoon salt

1/8 teaspoon pepper

Trim excess fat from beef tenderloin. Place beef tenderloin in a large shallow baking pan; bake, uncovered, at 400 degrees for 10 minutes.

Saute onion in butter until tender; add remaining ingredients. Bring to a boil; pour over tenderloin. Reduce heat to 325 degrees; bake 35 minutes or until a meat thermometer reaches 140 degrees to 170 degrees. Baste often with drippings. Slice tenderloin; serve with remaining drippings.

Makes 10 to 12 servings.