Beef Tenderloin with Potatoes

2 1/4 cups water
1 1/2 cups ketchup
3 envelopes Italian salad dressing mix
1 tablespoon prepared mustard
3/4 teaspoon Worcestershire sauce
1 whole beef tenderloin (3 - 4 pounds) trimmed
10 medium potatoes, peeled and quartered
1/2 cup butter or margarine, melted
1/2 teaspoon salt
1/4 teaspoon pepper

Combine the first five ingredients in a large resealable plastic bag. Pierce enderloin n several places; place in bag and turn to coat. Seal and refrigerate for 8 hours or overnight.

Place potatoes in a sacepan and cover with water. Bring to a boil; cook for 10-15 minutes or until crisp-tender; drain. Toss with butter, salt and pepper.

Place tenderloin on a rack in a roasting pan. Pour marinade into a saucepan; bring to a rolling boil. Boil for 1 minute; pour over meat. Arrange the potatoes around meat.

Bake uncovered at 375 degrees for 60-75 minutes, basting occasionally or until beef desired doneness ( for rare, a meat-therometer should reach 140 degrees, medium - 160 degrees, well done, 170 degrees). Slice, serve with pan juices and potatoes. Yield 10-12 servings.