Put the garlic, ginger, chillies and onion into a small food processor and whizz to a purée adding 1 tbsp water if you need to.

Heat 1½ tbsp oil in a large flameproof casserole or sauté pan. Brown the lamb all over in two batches, then lift onto a plate and put to one side.

Add the remaining oil and fry the spices in the same pan for 2 mins, adding a splash of water if they start to catch. Then add the onion purée and cook for 2 mins.

Add the lamb, tomatoes and stock. Stir, cover and cook for 45 mins.

Stir in the spinach then cook for another 45 mins or until the lamb is tender. If the sauce is looking thin, take the lid off for the last 20 mins of cooking to reduce it.

Scatter over the coriander. Serve with naan or rice.