Beef Sirloin Tip Roast

1 boneless beef sirloin tip roast (about 3 pounds)
1-1/4 cups water, divided
1 can (8 ounces) mushroom stems and pieces, drained
1 envelope onion soup mix
3 tablespoons cornstarch

Place a large piece of heavy-duty foil (21-in. x 17-in.) in a shallow roasting pan. Place roast on foil. Pour 1 cup water and mushrooms over roast. Sprinkle with soup mix.

Wrap foil around roast; seal tightly. Bake at 350° for 2-1/2 to 3 hours or until meat reaches desired doneness (for medium-rare, a meat thermometer should read 145°; medium, 160°; well-done, 170°).

Remove roast to a serving platter and keep warm. Pour drippings and mushrooms into a saucepan. Combine cornstarch and remaining water until smooth; gradually stir into drippings.

Bring to a boil; cook and stir for 2 minutes or until thickened. Serve with slice beef. Makes 10-12 servings.