1-First Step: Prepare the chicken by combining 1½ lbs boneless chicken thighs or breasts (cut into 1 to 1½ inch pieces), ½ cup Greek yogurt (or hung curd), ½ to 1 teaspoon Kashmiri red chili powder, 1 teaspoon garam masala, ½ teaspoon cumin powder, 1 teaspoon coriander powder, ¼ teaspoon turmeric, ½ teaspoon salt, 1 tablespoon lemon juice, 1 tablespoon kasuri methi (dried fenugreek leaves), 1 tablespoon ginger garlic paste (or ¾ tablespoon grated ginger plus ¾ tablespoon grated garlic), and 1 tablespoon oil (preferably mustard oil). Ensure the chicken is dry before marinating, then cover and refrigerate for at least 8 hours, preferably up to 48 hours.

2-Second Step: For the masala sauce, heat 3 tablespoons oil or ghee in a pan and sauté 1½ cups finely chopped onions with 1 teaspoon salt until deep golden. Add 1 green chili (optional) and 1 tablespoon ginger garlic paste, and sauté until aromatic.

3-Third Step: Reduce heat and add ½ to 1 teaspoon Kashmiri red chili powder, 1 tablespoon coriander powder, 2 teaspoons garam masala, and 1 to 1½ teaspoons cumin powder. Mix quickly to avoid burning.

4-Fourth Step: Add 1.1 lbs tomatoes (either pureed, chopped, or 1¼ cup tomato puree or passata) and cook on medium-high heat until the mixture thickens.

5-Fifth Step: Add 1 cup hot water (double if using cashews), bring to a boil, cover, and simmer for 12 to 14 minutes until thick. Optionally blend to smooth sauce if using canned tomatoes to reduce acidity.

6-Sixth Step: Grill the chicken tikka in the oven at 460°F (240°C) for 9-10 minutes on each side or until slightly charred, or cook in a hot skillet with oil for 3-4 minutes per side, or air fry for 6 minutes per side at 400°F (200°C).

7-Seventh Step: Add 1 to 2 teaspoons sugar and ½ cup heavy or whipping cream (or cashew cream) to the sauce and cook until thick and aromatic.

8-Eighth Step: Stir in the grilled chicken and 1 tablespoon kasuri methi, cook covered for 2-3 minutes until the chicken is tender.

9-Final Step: Garnish with 3 tablespoons heavy cream and 3 tablespoons finely chopped coriander leaves, then serve hot with Butter Naan, paratha, roti, or Basmati rice. For dietary adaptations, substitute proteins or dairy as required.