Optional Step: For a smoother sauce, blend all Marinade ingredients, except the chicken, in a food processor until smooth. (This step is optional and typically not done).
Marinade: In a bowl, mix the Marinade ingredients with the chicken. Cover and refrigerate for at least 3 hours, preferably overnight, or up to 24 hours.
Cooking the Chicken: Heat ghee, butter, or oil in a large frying pan over high heat. Remove the chicken from the marinade without wiping off the excess. Place the chicken in the pan and cook for about 3 minutes, until the chicken turns white all over. Note: The chicken will not brown due to the marinade.
Making the Sauce: Add tomato passata, cream, sugar, and salt to the pan. Pour in any leftover marinade from the bowl as well. Reduce the heat to low and let it simmer for 20 minutes. Taste and adjust salt if necessary.
Serving: Garnish with coriander or cilantro leaves if desired, and serve with basmati or white rice.