This is a simple recipe for sirloin tip roast. You will need 3 pounds of sirloin tip, 1/-1/4 cups of water. 1 can of mushroom stems and pieces drained, 1 envelope onion soup mix and 2 tablespoons of cornstarch. Place heavy duty foil in a 21x17 inch roasting pan. Put the roast on the foil. Pour 1 cup of the water and mushrooms over the roast. Sprinkle with soup mix and wrap foil around the roast sealed tightly. Put into a preheated oven for 2-1/2 to 3 hours or until it reaches it's desired state of being done. Put roast on platter and drain drippings and mushrooms in a saucepan. Bring to a boil. Mix corn starch with 1/4 water and add to drippings until thickened.