Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   1                    beef tenderloin -- (3 to 4 lb.)
     1/2  cup           chopped onion
   1 1/2  tablespoons   butter -- melted
   1      cup           dry sherry
   3      tablespoons   soy sauce
   2      teaspoons     dry mustard
     1/8  teaspoon      salt
     1/8  teaspoon      pepper

Preparation:

Trim excess fat from beef tenderloin. Place beef tenderloin in a large shallow baking pay; bake, uncovered, at 400 F for 10 minutes. Saute onion in butter until tender; add remaining ingredients. Bring to a boil; pour over tenderloin. Reduce heat to 325 F, bake 35 minutes or until a meat thermometer reaches 140 to 170. Baste often with drippings. Slice tenderloin; serve with remaining drippings.