1 Heat the oven to 150°C (130° fan) 300°F gas 2.
2 Heat the oil in a flameproof casserole dish and brown the meat on all sides. Add the onion to the dish and cook until softened.
3 Sprinkle in the flour and cook for 1 minute. Stir in the stock, season to taste and bring to a boil.
4 Add 3 oregano sprigs, cover and cook in the oven for 3-4 hours until the meat is very tender. Add the chestnuts for the last 25 minutes of the cooking time.
5 Garnish with remaining oregano sprigs