In a large skillet over medium high heat, combine the ground beef and the onion and saute for 10 minutes, or until the meat is browned and the onion is tender.
In a large pot over high heat, combine the soups, mushrooms, soy sauce, steak sauce, Worcestershire sauce, vinegar, lemon juice, sugar, curry powder to taste, garlic powder, cayenne pepper and oregano and season with salt to taste.
Bring to a slow boil, stirring often to prevent burning. When hot, add the meat and onion mixture.
In a separate small bowl, combine the cornstarch and water, stirring until cornstarch is dissolved, and add slowly to the sauce, stirring well. (Note: This will thicken the sauce so only do this if you feel it's necessary.)