1. Make tandoori chicken according to my recipe. The chicken will be put into the sauce just before serving. Do not simmer the chicken the chicken in the sauce if you insist on using white (breast) meat or it will be dry and nasty. Also, it will denature the tandoori aspect of the meat—the meat should not be part of the sauce, just "inside" the sauce.
2. Heat ghee or oil. Clarify onions and cook remaining aromates on low heat (up to 5 minutes). Bloom spices.
—According to Daniel Raj, what is done with these aromates is the whole secret to a good Indian dish. As a general principle, the longer you cook, the darker your curry will be. Use tumeric, tomatos, paste or sauce, or food coloring to impart the color you want and to keep it from becoming greyish.
3. Add tomato ingredients and continue to simmer. Add yoghurt and cream, then additional chicken stock, sugar and salt. Raise to a boil, then drop heat and simmer covered for 10-15 minutes.
—You can use one of those hand-held mixers for zapping up soup ingredients into a velouté if you like it smooth and creamy. Mine just fits inside the tomato can. Or just process your diced tomatoes in a blender. You want the sauce to be smooth except for chicken and onions.
4. Add chicken and fold to cover it in sauce. Quickly garnish with the cilantro leaves and serve with rice and naan.