01 - Combine all chicken marinade ingredients in a large bowl. Add chicken, toss to coat evenly, cover, and refrigerate for at least 30 minutes or up to overnight to deepen flavor.
02 - Rinse basmati rice under cold water until clear. In a medium saucepan, combine rice, water, and salt. Bring to a boil, reduce heat, cover, and simmer for 12 to 15 minutes until water is absorbed. Remove from heat and let rest covered for 5 minutes. Fluff with a fork.
03 - Heat vegetable oil in a large skillet or Dutch oven over medium-high heat. Add marinated chicken pieces in batches and sear until browned on all sides but not fully cooked. Remove chicken and set aside.
04 - In the same pan, add chopped onion and sauté for 4 to 5 minutes until soft and golden. Add garlic and grated ginger; cook for 1 minute until fragrant.
05 - Stir in ground cumin, paprika, coriander, and optional cayenne pepper. Toast spices for 1 minute, then add crushed tomatoes and sugar. Simmer for 10 minutes, stirring occasionally.
06 - Stir in heavy cream and return chicken along with any accumulated juices to the pan. Simmer for 10 to 15 minutes until chicken is fully cooked and sauce has thickened. Season with salt to taste.
07 - Warm naan breads according to package instructions or in a hot skillet until heated through.
08 - Plate chicken tikka masala garnished with fresh cilantro alongside prepared basmati rice and warm naan.