Place the beef in a small pan and cover with water. Season with salt. Bring to the boil, cover, then reduce heat to a simmer and cook gently for 1 to 2 hours, till beef is fork tender. Remove and cut beef into cubes, and reserve the remaining juices in the pan.
In a dry frying pan over medium high heat, toast the chillies, peppercorns, cinnamon, cardamom, cumin and coriander till fragrant. Using a spice grinder, process the toasted spices to a fine powder, then add the garlic and ginger to create a paste.
In a large saucepan or casserole, heat oil or ghee and add the curry leaves and chopped onions; fry till the onions turn golden brown. Add the spice paste and mix well. Then add the beef and its stock. Bring to the boil.
Once boiling, add the potatoes, tomatoes, green beans and additional salt to taste. Cover, then reduce heat to a simmer and cook gently till potatoes are tender. Finish by adding the tamarind juice; cook a few minutes more and then serve hot with pulao or basmati rice.
Instead of starting with whole spices and grinding them yourself, you can use ground spices. Toast the ground spices gently, then combine with the ginger and garlic to make a paste.
Instead of a fresh tomato, you can opt to use a spoonful or two of tomato puree.