Heat a large roasting pan on the hob and add oil, onion, garlic and ginger. Add the shoulder of lamb and brown well.
Add the spices and coat meat in them well. Add the tomatoes, chick peas, stock and potatoes. Bring to the boil, cover with foil and place in preheated oven. Cook for about 2 hours until the meat falls off the bone. Add the spinaach in the last 10 minutes of cooking and allow to just wilt slightly.
Serve in chunks with Indian breads or steamed rice.