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. If not, then substitute with two tablespoons of garam masala and 1 teaspoon of ground black pepper.
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 translucent.Add the garlic and ginger. Saute for 30 seconds.
Now add the ground 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. Let the chicken cook in the spices for 1 minute.
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.