Cut beef into 3 cm cubes. Heat oil in a large heavy saucepan, add beef and cook until browned all over. Remove with a slotted spoon and set aside. Add onion, cloves and cardamom to pan; cook, stirring, about 8 minutes, until onion is soft and golden brown. Stir in chiles, gingerroot, garlice, corinder and turmeric; cook 2 minutes. Return beef to pan, add water and cover. Simmer 1 hour. Stir in tamarind nectar and salt; simmer another 20 to 30 minutes, until beef is tender. Serve, garnished with lettuce leaves.
Note on tamarind nectar: Soak a walnut-sized piece of tamarind paste in one cup boiling water about 20 minutes, then squeeze in cheesecloth to extract liquid; discard pulp.
Store in refrigerator up to one week.