Cut the chicken into strips or cubes and put aside
Heat the oil and add the onions and cook until they start to soften which will be about 5 or 6 mins
Once the onions have started to brown add the chillies, garlic and ginger; cook for a further 2-3 minutes
Then add the turmeric, cumin, coriander, curry leaves and chilli powder and leave to cook for a further minute or so
In that time, season the chicken with salt and pepper, then add to the pan and cook stirring until the chicken begins to go golden brown all over
At this stage you’ll want to add the water and the chopped tomatoes and bring to boil
Reduce the heat to a simmer and cover the pan stirring ever so often. Let it simmer for about 30 minutes and add more water as needed if it begins to stick or the sauce becomes too dry – remember to stir well if you do need to add water
At the end of the 30 mins, stir in the garam masala and leave uncovered for another 10 mins, again taking care not to let it dry out