Wash the lentils in cold water. If necessary, soak them overnight, and then drain. Soaking shortens Cooking time and prevents splitting. However, most lentils are tender enough to need little or no soaking.

Trim the fat from the lamb and dice the meat into 1 in (25 mm) cubes. If you are using fresh spinach, wash it thoroughly. Finely slice the onion and garlic, and peel and slice the carrots into rounds.

Place 1/2 oz (15 g) of the butter and the olive oil into a large flameproof casserole. Heat until the butter melts and sizzles, and then add the lamb cubes, stirring until they are sealed and browned. Leaving the fat in the casserole, remove the lamb with a slotted spoon and keep it to one side.

Add the onion, garlic and carrots to the casserole and cook over a moderate heat until softened. Next add the tomatoes, lamb pieces, 1 teaspoon of salt, 1/2 teaspoon of pepper, optional chillies, lentils and enough water to just cover the mixture. Stir in the cumin and simmer for 1 1/4 hours, until the lentils are cooked. Add a little more water if the mixture begins to dry. Set the mixture aside when cooked.

Cook the spinach in 1 oz (25 g) of the butter with a little salt and the ground coriander. Reheat the lentil mixture and stir in the cooked spinach. Sprinkle with chopped parsley or fresh coriander and serve.