In a mixing bowl, take ½ kg of chicken (cut into small pieces) and add ½ tsp of turmeric powder, 1 tbsp of lemon juice and salt as required. Mix the ingredients with the chicken pieces nicely and keep aside for 30 minutes.
In the meantime, to make the Chettinad masala, heat 1 tbsp of sesame oil in a frying pan. When the oil is hot, add 3 tbsp of coriander seeds, 1 tsp of fennel seeds, 1 tsp of cumin seeds, 1 tbsp of black peppercorns, a blade of mace, 8 pieces of cloves, 2 pieces of cinnamon (inch-size stick), a piece of star anise, 2 pieces of green cardamom, and 1 piece of black cardamom. Sauté them for a minute or so while keeping the flame on medium.
Now, add 2 pieces of bay leaves (torn in half), 2 pieces of black stone flower, and 8 cloves of garlic (peeled, whole) to it and sauté them for two minutes on a medium flame as well. At this stage, add 6 pieces of red chilies (Bedgi, whole without the stalk) and toast these spices until all the spices and chilies turn to deep brown in color. When they do, turn off the flame of the gas stove and transfer the toasted spices onto a plate. (Pro tip: It is imperative to transfer the spices to stop the cooking process and let it cool down to room temperature).
In the same pan roast ¼ cup of coconut (fresh, grated) on a medium flame. Stir continuously until it turns brown in color and transfer it onto the plate with toasted spices and let it cool down to room temperature as well.
Once the roasted spices and coconut have cooled down, transfer them into a mixer and add 1 piece of ginger (inch size), 1 tsp of tamarind paste, and a pinch of fenugreek seeds to it.
Add water as required and grind everything to a fine paste. Keep it aside.
Now, to prepare the seasoning, heat 2 tbsp of sesame oil in a pan. While it heats up, slice 15 pieces of shallots and sauté on medium flame until shallots are golden brown. Now, add 3 sprigs of curry leaves and sauté for a minute or so.
Now, add the marinated chicken and turn the flame on high and sauté for 2 to 3 minutes.
Once the chicken has seared well, add the Chettinad masala mix along with water and salt as required. Mix them all nicely and bring it to a boil. (Pro tip: Always check and add salt at this stage because you have already added a lot of salt in different stages of the cooking process).
Now, lower the flame, cover the pan with a lid and let it cook for 15 to 20 minutes.
Your tasty and spicy homemade Chicken Chettinad is ready! Transfer it to a serving bowl, garnish it with a few sprigs of fresh coriander leaves and serve hot with steamed rice.