Cook the Aromatics
Heat oil in a large skillet or pot over medium heat. Add chopped onion and cook for 5–7 minutes until soft and golden. Stir in garlic, ginger, and green chilies. Cook for another 1–2 minutes.
Toast the Spices
Add cumin, coriander, garam masala, paprika, turmeric, and cayenne. Stir for 30 seconds until fragrant, allowing the spices to bloom.
Build the Base
Stir in tomato paste and cook for 1 minute. Add crushed tomatoes and water or broth. Simmer the sauce for 5–7 minutes to thicken and deepen in flavor.
Add the Chicken
Add the chicken pieces to the sauce, stirring to coat. Cover and simmer on medium-low for 15–20 minutes until chicken is cooked through and tender.
Finish the Curry
Uncover and simmer for another 5 minutes to reduce the sauce slightly. Adjust salt and add lemon juice if desired for brightness.
Garnish and Serve
Top with fresh cilantro and serve hot with basmati rice or warm naan.