Mix the chicken with the yoghurt and spices and put to one side.
Fry all the whole spices and the whole chilli in the oil for 30 seconds until fragrant, then add the chopped onion and cook for 10-20 minutes, stirring a couple of times until soft and lightly golden.
Add the garlic, ginger, a pinch of salt and ground spices with the tomato puree and cook, stirring a few times for 30 seconds. Add the chicken and yogurt to the pan and stir until it becomes creamy.
Add 200ml water and cook for 35 minutes until the chicken is tender, adding a pinch of salt to taste.
Add the tomatoes and cook for 5 minutes until softened but still holding their shape.
Warm the naan breads according to the packet instructions.
Meanwhile, rub a pinch of salt into the sliced onion, then rinse and allow to drain. Serve topped with the salted onion and coriander and with the warmed breads on the side.