In a Dutch oven over medium-high heat, brown roast on all sides in oil; drain. In a large skillet, saute onions in 2 tablespoons of butter until tender. Add the water, soy sauce, soup mix, garlic and, if desired, browning sauce. Pour over roast., Cover and bake at 325° for 2-1/2 hours or until meat is tender., Let meat stand for 10 minutes, then thinly slice. Return meat to pan juices. Split bread lengthwise; cut into 3-in. sections. Spread with remaining butter. Place on a baking sheet., Broil bread 4-6 in. from the heat for 2-3 minutes or until golden brown. Top with beef and onions; sprinkle with cheese. Broil for 1-2 minutes or until cheese is melted. Serve with pan juices.