Add the oil to a pan and when hot stir-in the onions.
Cook over low heat until soft (about 10 minutes).
Now add the meat and cook, stirring frequently, until the meat is browned.
Stir in the tomatoes and cook for 5 minutes, then add the wine and bay leaf.
Season with salt and black pepper and add just enough water to almost cover the meat.
Bring the mixture to a boil then reduce to a simmer, cover and cook gently for about 20 minutes, or until the lamb is tender.