1.Take the chopped chicken and coat it in the cumin, ground coriander and turmeric then leave it to marinade in the fridge while you make the sauce.

2.To make the sauce, fry the roughly chopped onions with the garlic and green chilli in a large pan until browned. Add the water to the onion mixture and simmer this for around 20 minutes.

3.While that is simmering, put the plum tomatoes in a food processor and give it a good whizz - aim for a smooth consistency. Heat another large pan and gently fry the ground coriander, cumin and turmeric in a splash of oil for about a minute. Add the tomato 'sauce' to this pan and simmer for around 10 minutes.

4.Next give your onion mixture a good whizz in the food processor and add it to the spiced tomato sauce. Give it a stir and simmer for 20 minutes. You can make large batches of this sauce and freeze it for later use.

5.Fry the marinaded chicken in oil and stir continuously. After a few minutes, turn down the heat and add the other half of the chopped onion, the red pepper and chillis. Stir this until the onions and pepper soften (and the chicken is cooked, of course).

6.Add the earlier prepared sauce to the cooked chicken and simmer for around 10-20 minutes. Just before you dish it up, stir in the garam masala and chopped coriander leaves. Serve with basmati rice or naan bread.