In a small bowl, combine minced garlic, minced ginger, turmeric, garam masala, cumin, coriander, and salt. Stir well. In another bowl, whisk together yogurt, half the spice mixture, and 2 teaspoons lemon juice. Halve chicken breasts, then pound them to an even thickness using a meat mallet or bottom of a frying pan. Add chicken to the yogurt mixture, ensuring it’s coated well. Cover tightly or transfer to a resealable bag and refrigerate for at least 6 hours, preferably 24 hours. Cover and chill remaining spice mixture.
In a large, heavy pan, heat vegetable oil over medium heat. Add finely chopped onion and cook until it starts to soften, about 2–3 minutes. Stir in tomato paste, ground cardamom, and red pepper flakes. Cook, stirring frequently, until tomato paste darkens and onion is soft, about 5 minutes. Add remaining half of spice mixture and cook, stirring often, until the bottom of the pan begins to brown and everything is very fragrant, about 4 minutes (reduce heat if necessary to avoid burning).
Add crushed tomatoes to mixture and bring it to a boil over increased heat, then reduce heat. Simmer, stirring often and scraping the bottom of the pot, until the sauce thickens, about 8 minutes. Stir in heavy cream and cilantro. Simmer over low heat, stirring occasionally, until sauce thickens further, about 30–40 minutes. Optionally, transfer sauce to a blender or use an immersion blender to puree until smooth. Taste sauce for any additional seasoning/salt. Depending on tomatoes, you may need 1–2 teaspoons sugar to balance acidity.
(See note 1.) Preheat a grill or grill pan to medium-high heat (about 400°F). Oil grill generously by drenching a rolled-up paper towel in vegetable oil and rubbing it over grill grates using tongs (important step, do not skip). Remove chicken from marinade and discard any excess. Grill chicken, turning once halfway through, for about 4–6 minutes per side or until thickest part registers 165°F and juices run clear. Transfer chicken to a plate, cover with foil, and let it rest for a few minutes to redistribute juices. Chop into bite-size pieces, then stir into the sauce until coated. Serve over freshly cooked rice with warmed naan. Garnish with additional chopped cilantro as desired.
Notes
Note 1: If you don't have a grill or grill pan, follow this alternate cooking method: Heat 1 tablespoon oil in a nonstick pan over high heat until smoking. Add half the chicken (pre-cut into 2-inch pieces before marinating) in a single layer and let it cook for about 2 minutes or until charred. Flip each piece and cook the other side until charred (chicken won’t be fully cooked, just charred). Remove chicken and set aside. Clean pan by scraping out charred bits and wiping it clean. Add more oil and repeat with the remaining chicken until all is charred. Then, add charred chicken to the sauce and simmer, stirring occasionally, until fully cooked through, about 2–3 minutes.Nutrition Note: Nutritional information does not include naan or rice.Storage: Keep Chicken Tikka Masala in airtight containers in the fridge for 3–5 days. Reheat on the stove; adjust sauce thickness with water or cream. Freeze for longer storage; thaw in fridge and reheat on low to avoid curdling cream.