Preheat the oven to 180C/350F and salt the chicken thighs all over.
Heat the ghee in a deep pan and brown the chicken until golden. It will take up to 15 minutes.
Scatter the onions slices and garlic cloves over the chicken. Mix ground coriander, smoked paprika, curry powder, cumin seeds, ginger and lemon zest with the milk and pour over the chicken.
Cover with the lid and braise in the oven for 50 minutes, then uncover and cook for 15 minutes longer until the liquid is reduced and the chicken skins are browned and crispy.
Notes
I like to serve this dish with rice and mango chutney.