Marinate the chicken pieces in curd, red chilli powder, turmeric powder, and salt for 30 mins. If you need to leave it longer, refrigerate it.
Heat oil and add the mustard seeds and fennel seeds. When they pop and sizzle, add the sliced onions and green chillies. Reduce flame to medium-low and fry the onions until they turn golden brown. The amount of oil at this stage should be on the higher side so add a bit more of you feel it's not.
Next, add the coriander powder and the freshly crushed masala (cloves, etc) and fry for 10 seconds. Top off with the ginger garlic paste and sautè for another 30 seconds until the mixture turns fragrant.
Add the tomatoes, food colour (if using) and curry leaves and mix well. Cook until the tomatoes turn soft - about 3 mins.
Dunk the marinated chicken pieces into this mixture and increase the flame to medium-high. Cook stirring frequently until the chicken pieces begin to roast. You don't have to add any water, the meat will let out water as it cooks. Adjust salt and keep roasting until the chicken is cooked soft. This will take about 20-25 mins. If you feel the chicken is not cooking well, cook closed to speed up the process. The curry will be watery in this case so once the chicken is cooked, cook on an open flame until your desired consistency is reached.
When the chicken has roasted and most of the water has been cooked off, add the chicken masala and mix well. Cook for another minute and remove from fire.
