Place the meat, lentils, split peas, pumpkin, potatoes and turmeric in a large, heavy-based saucepan. Season well and pour in enough water to cover. Bring to the boil, reduce the heat and simmer gently for 1–1½ hours or until the meat is tender. Remove the meat from this mixture and set aside. Use a hand-held electric mixer to purée the vegetable mixture until fairly smooth. Return the meat to the pan and set aside.
Meanwhile, heat 3 tablespoons of the oil in a large frying pan and stir-fry the onions over a gentle heat for 15–20 minutes or until golden brown. Reserve half the onions and add the rest to the meat mixture.
Heat the remaining oil in the frying pan and fry the ginger, garlic and curry powder over a medium heat for 2–3 minutes. Stir this mixture into the meat curry, along with the tamarind and sugar. Stir to mix well and simmer the curry for 10–15 minutes.
Remove from the heat and serve immediately, garnished with the reserved onions and coriander leaves. Serve with yellow basmati rice or a rice dish such as Carrot & Pea Pilaf (see