Preheat the oven to 160°C/320°F/Gas Mark 3. Brown the meat, garlic and onion with the olive oil in a large flameproof casserole (cocotte). Add the bay leaf, thyme and carrots, and enough water to cover the meat by at least a couple of centimetres. Bring to a simmer and remove any scum that rises to the top. Once all the scum is removed, cover the pan and transfer to the oven. Cook for 1½ – 2 hours or until the meat is tender.