Marinate Chicken: Mix yogurt, lemon juice, ginger-garlic paste, turmeric, chili powder, and salt. Coat chicken and marinate for at least 2 hours (overnight is best).
Cook Chicken: Traditionally done in a tandoor, but a grill pan or oven works too. Cook until lightly charred.
Prepare Curry Base: Heat butter in a pan, add tomato purée, and simmer with chili powder, cashew paste, and salt.
Add Chicken and Cream: Add grilled chicken pieces, cream, and fenugreek leaves. Simmer until flavors meld.
Serve: Garnish with fresh coriander. Serve with naan, roti, or basmati rice.