In a frypan over medium heat, brown the beef mince with the onion until the meat is no longer pink and the onion is soft; drain fat.
In a casserole dish or large saucepan combine the beef mince mixture and tomatoes. Season with Worcestershire sauce, chilli powder, salt and pepper. I just keep adding stuff until it tastes good. Bring to a boil and let simmer for 15 to 20 minutes to blend flavours.