Grind all the masala ingredients in a coffee grinder using a little water to get a thick, creamy paste. Place chicken in a shallow bowl, sprinkle ½ tsp ground turmeric and a tsp of salt, mix well, cover and keep in the fridge for 2 hours or even overnight. Allow the chicken to come to room temperature before you begin cooking (putting cold meat in a hot pan can make it tough).
Heat 2 tbsps of vegetable oil in a wide pan, and when it’s medium-hot, toss in the cardamom, cloves, cinnamon sticks and bay leaf taking care not to burn the spices.
Saute the spices for 10-15 secs and add the grated onion. Keep the flame on low-medium and fry the onions, stirring intermittently till they are golden and caramelised. Add a tsp of sugar to help with the browning.
Add the pounded ginger and garlic to the caramelised onions and continue to fry for 3-4 mins till they stop smelling raw.
Now lower the flame, remove the pan from the stove and add the ground masala paste stirring well (add a tbsp or two of water to loosen the mixture). Return the pan to the flame and cook the masala for 5-7 minutes, till you see tiny bubbles of oil separating on the edges of the masala.
Now is the time to put in the chicken and season the curry with salt. Mix well to coat the meat with the masala. Pour 250 ml water, toss in the curry leaves, cover the pan, and cook the curry on a medium flame for 15-20 minutes.
Once the chicken is almost done, add the drumstick pieces, cover and cook for a further 10 minutes(adding if the sauce is too thick). Sprinkle garam masala, simmer for a minute more till the curry is done.