01 - In a large bowl, combine Greek yogurt, lemon juice, ground cumin, ground coriander, turmeric, garam masala, smoked paprika, salt, minced garlic, and grated ginger. Add chicken pieces and toss thoroughly to coat. Cover and refrigerate for at least 30 minutes or overnight for enhanced flavor.
02 - Rinse the basmati rice under cold water until the water runs clear. Drain thoroughly.
03 - Bring water, salt, and butter (if using) to a boil in a medium saucepan. Add the rinsed rice, reduce heat to low, cover, and cook for 15 minutes. Remove from heat and let stand, covered, for 10 minutes. Fluff rice with a fork before serving.
04 - Heat vegetable oil or ghee in a large skillet or Dutch oven over medium-high heat. Shake excess marinade from chicken pieces and cook in batches until browned on all sides, approximately 4 to 5 minutes per batch. Remove browned chicken and set aside.
05 - In the same pan, add finely chopped onion and sauté until soft and golden, about 5 minutes. Add minced garlic and grated ginger; cook for 1 minute until fragrant.
06 - Stir in ground cumin, ground coriander, paprika, garam masala, and chili powder. Cook for 1 minute to release aromas.
07 - Add crushed tomatoes and sugar to the pan, then simmer for 10 minutes while stirring occasionally.
08 - Return the browned chicken pieces to the sauce. Simmer gently for 10 to 12 minutes until the chicken is fully cooked.
09 - Stir in heavy cream and allow to simmer on low heat for 3 to 4 minutes until the sauce is creamy and heated through. Season with salt to taste.
10 - Serve the chicken tikka masala hot over basmati rice. Garnish with chopped fresh cilantro.