Sirloin tip roast, located next to the tender sirloin area of the beef, is a juicy, flavorful cut of meat. While sirloin tip roast is tender enough for dry-roasting, it becomes even juicier when roasted in an oven bag. Sirloin tip roast is also known as round tip roast or tip sirloin roast. Cook this tasty roast as is, or spice it up with your choice of seasonings. For a one-pan meal, add vegetables such as potatoes, carrots or celery.
Preheat your oven to 325 degrees F.
Place all-purpose flour in the oven bag. Shake gently to distribute the flour.
Lay the oven bag in a rectangular roasting pan. Use a pan with sides at least 2 inches high.
Place onion soup mix and water in the bag. Knead the bag with your hands to mix the water and soup with the flour.
Poke 10 to 15 holes in the sirloin tip roast with the tip of a paring knife. Insert a piece of garlic clove into each hole.
Place the roast carefully in the oven bag. Add chunks of potatoes or whole, new potatoes, onions, carrots and celery, if desired. You can also add chunks of turnips, parsnips or rutabagas. Cut the vegetables in uniform pieces so they finish cooking at about the same time.
Tie the oven bag closed, using the heatproof tie provided with the bag. Use the tip of a paring knife to make three or four small holes in the bag, near the tied end. Arrange the oven bag so that no part of the bag extends beyond the pan.
Cook the roast for about three hours, or until the meat is tender. Transfer the roast to a serving platter.