I used 2 lamb shanks when I made this but you could use the same quantities for 4, as this makes plenty of sauce.
Brown the shanks in olive oil over a high heat, then remove and set aside. Add to the pan 2 celery sticks, 4 shallots or a small onion and 2 carrots all roughly chopped, along with 4 peeled garlic cloves.
Cook the vegetables until they start to take on some colour then put the shanks back in the pan. Now add a tablespoon of flour and stir well, then pour in half a bottle of good red wine and add 2 or 3 sprigs of thyme and a bay leaf. Add 500ml of beef stock and season well. Bring to the boil then reduce the temperature right down to barely a simmer. Put a lid on and either cook on the hob on the lowest heat or in the oven at about 150c for about two hours, turning the shanks occasionally.
When the lamb is almost falling off the bone remove it and then sieve the liquid into a pan and discard the vegetables and herbs. Now simmer the liquid to reduce it to a sauce and serve with the lamb.