Heat the oil in a heavy frypan and fry the onion over medium heat, stirring regularly.
In a saucepan, combine carrots, celery, thyme, bay leaves and 4 cups water and bring to the simmer. Add the onions. In the frypan that you cooked the onions in, simmer the tomatoes over low heat until soft, then add to the soup.
Place the mince in a bowl and add pepper, nutmeg and soy sauce. Mix well and form into small balls.
In a separate saucepan, bring 2 cups water to the boil and simmer the meatballs 1/2 hour. Remove bay leaves from the soup and add the crumbled 1/2 stock cube. Finally add cooked meatballs and serve with bread.