1Gently fry the onion and garlic in the oil for a couple of minutes until beginning to soften, then add the mince. Raise the heat and cook for 5 minutes, stirring from time to time, until the meat is no longer pink.
3Stir in the beans, tomatoes, stock, chillies, chocolate and plenty of salt and pepper. Bring to the boil, cover and simmer very gently for 1 hour, or longer if you have the time. (You can make it up to a day ahead to this point, then cool and chill.)
5Ladle into mugs or large cups and scatter with herbs, cheese and black pepper. You’ll need spoons to eat it.