1 1/2 tbsp toasted paprika
1 tbsp toasted ground coriander seed
1 tsp ground turmeric
1/2 tsp cayenne pepper
6 cloves garlic, minced
1/2 tbsp fresh ginger, grated, divided
1 c yogurt
1/3 c fresh juice from 2 lemons, divided
2 tbsp butter or ghee
1 medium onion, diced
1 (14-ounce) can whole peeled tomatoes
1/4 c roughly chopped cilantro leaves
1/2 c heavy cream
Place the chicken pieces on a cutting board with the flesh-side up. Score deeply at 1-inch intervals with a sharp knife. Place in a large rimmed baking dish.
Combine cumin, paprika, coriander, turmeric, and cayenne in a small bowl and mix well. Set aside 3 tablespoons of spice mixture. Combine remaining 6 tablespoons spice mixture, 8 cloves garlic garlic, 2 tablespoons ginger, yogurt, 1/2 cup lemon juice, and 1/4 cup salt in a large bowl and whisk to combine. Pour marinade all over chicken pieces, using hands to coat every surface. cover loosely and refrigerate. Refrigerate and allow to marinate for at least 4 hours and up to 8, turning occasionally.
Meanwhile, heat butter or ghee in a large Dutch oven over medium-high heat until melted and foaming subsides. Add onions, remaining 4 tablespoons grated garlic, and remaining 2 tablespoons ginger. Cook, stirring frequently, until dark and beginning to char in spots, about 10 minutes. Add reserved spice mixture and cook, stirring frequently, until fragrant, about 30 seconds. Add tomatoes and half of cilantro, scraping up any browned bits from bottom of pan with a spoon. Simmer for 15 minutes, then puree using a hand blender or by transferring to a tabletop blender in batches.
Stir in cream and remaining quarter cup lemon juice. Season to taste with salt, then set aside until chicken is cooked.
We cooked the chicken on a stovetop grill. We brush it with a little bit of oil and allowed it to preheat for 5 minutes.
Wipe excess marinade off chicken and place over hot side of grill. Grill without moving until well charred, 5 to 7 minutes. Flip chicken and cook until second side is charred, another 4 to 5 minutes. Transfer to cutting board and allow to rest 10 minutes.
Cut chicken into bite-sized chunks. Transfer chicken chunks to pot of sauce. Bring to a simmer over medium heat and cook, stirring frequently, until chicken is just cooked through, about 10 minutes. Sprinkle with remaining cilantro, then serve immediately with rice or grilled Naan.