Set a large dutch oven (or saucepot) over low heat. Add the ghee, red onion, cilantro, garlic, and ginger. Sauté, stirring occasionally, for 10-12 minutes until the onions are very soft.
Meanwhile, cut the chicken thighs into 1-inch pieces.
Add the Madras curry powder, garam masala, salt, and Kashmiri chili powder. Stir and sauté another 5 minutes.
Raise the heat to medium. Add the tomatoes and coconut milk. Stir well, then simmer for 10 minutes.
Stir the chicken pieces into the sauce. Cover and simmer for 15-20 minutes, stirring occasionally.
When ready to serve, stir the lemon juice into the curry. Then spoon over basmati rice and serve with extra cilantro.
