In a kadai, heat the butter, add minced onions and fry until golden brown in colour.
Next add the minced ginger garlic, coriander, chilli powder, turmeric, salt and fry for a minute until you get fragrant smell.
Next add the pureed tomato, tomato paste and cook for 3-4 mins until the mixture starts bubbling.
Later add kasthuri methi, milk and the cubbed chicken. Cover the kadai until and cook for 8-10 mins until the chicken is soft. If the chicken lets out water, just check once or twice and give the curry a good stir. Also keep the heat in sim mode.
After the chicken is cooked soft, open the lid and cook for a minute or two. Add little water at this stage if the gravy is thick.
Finally after it is done, add the garam masala or chicken masala and the cream or cashew paste. Later give it a good stir, but do not boil.
In the end garnish with coriander leaves, adjust salt if needed and remove it from fire.
Have it with hot with tawa naan, vegetable pulao or jeera rice.