In a large frying pan over medium heat, cook the beef mince and onions until beef is evenly browned; do not drain. Season with salt and pepper to taste. Stir in flour 1 tablespoon at a time, until beef juices have been absorbed.
Stir in tomatoes, tomato juice and water. Simmer on low heat to thicken.
Stir in nutmeg and sugar; simmer until flavours are blended well. Serve on toast.