Combine the garlic, ginger, turmeric, oil and chicken in a bowl. Add the chicken and rub in the marinade. Cover and transfer to the fridge for at 1 hour to marinate (you can marinate overnight for extra flavour if you prefer).
Blitz the coriander, mint, onion, chilli, garlic and curry powder together in a food processor to form a paste.
Add the curry paste to the chicken marinade mixture and stir well to combine.
Fry off the mix in a nonstick fry pan and reduce heat to a simmer. Cook for 30 minutes, stirring occasionally. The fat will release from the chicken, so no need for extra oil here.
Add the cornflour mixture to and stir until the sauce starts to thicken. Stir through the yoghurt and add sugar to taste.
Season with salt and pepper and cool the filling to room temperature. Pre heat oven to 180CSpoon into a medium pie dish and cut a round of pastry to form a lid. Baste with egg and sprinkle with nigella seeds or sesame seeds. Cut a small slit on too to allow air to escape.
Bake for 30 minutes or until golden. Serve with tomato kasundi or chilli sauce.
