Place roast in a 5-qt. slow cooker; sprinkle with soup mix, browning sauce if desired, salt and pepper. Pour water over meat. Cover and cook on low for 8-10 hours or until meat is tender. Remove roast to a cutting board; let stand for 5 minutes. Add vegetables to slow cooker. Cube beef and return to slow cooker. Cover and cook on low for 1-1/2 hours or until vegetables are tender. Combine cornstarch and cold water until smooth; stir into stew. Cover and cook on high for 30-45 minutes or until thickened.