- 2 1/4 cups water
- 1 1/2 cups ketchup
- 3 (.7 ounce) packages Italian salad dressing mix
- 1 tablespoon prepared mustard
- 3/4 teaspoon Worcestershire sauce
- 1 (3 pound) whole beef tenderloin
- 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 tenderloin in several places; place in bag and turn to coat. Seal and refrigerate for 8 hours or overnight.
- Place potatoes in a large saucepan 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 saucepan; bring to a rolling boil. Boil for 1 minute; pour over meat. Arrange the potatoes around meat.
- Bake, uncovered, at 375 degrees F for 60-75 minutes, basting occasionally, or until beef reaches desired doneness (for medium-rare, a meat thermometer should read 145 degrees F; medium, 160 degrees F; well-done, 170 degrees F). Slice; serve with pan juices and potatoes.