Marinate the chicken with turmeric,Salt and Ginger Garlic paste for 15 minutes to 12 hours.
In a spice blender, blend all the whole spices - coriander seeds, black peppercorns, Cumin, Cinnamon, Fennel Seeds, Cloves, Poppy seeds & Red chili into a coarse powder and keep aside.
In a heavy-bottomed pot, Heat the oil.
Add the Onions , curry leaves, and green chili to the hot oil. Sauté till they start turning golden brown.
Now add the spice blend. To make the curry less spicy, add only half the spice blend. Sauté for about 30 seconds. Add a splash of water if it starts to burn.
Add the Tomatoes and cook until they start disintegrating. About 10 minutes. You can squash the tomatoes to speed up the process.
Add the Chicken next and mix well. Turn the pieces Skin side down to enable caramelization. Do not move for about 4-5 minutes.
Add about 1 cup water, salt to taste(around 1 tsbp), and let it simmer for 30 minutes or so.
Mix it up. Garnish with coriander and serve hot.