Place the onion, chilli and ginger/garlic paste in a blender and blend into a smooth paste. Add a few drops of water if required
Heat the oil in a large pot and add the cinnamon stick, bay leaf and curry leaf. Once it becomes fragrant add the onion paste
Cook until the onion is slightly brown
Add the curry powder and chilli powder, cook for a minute
Add the tomatoes and chicken and cook with the lid off, for about 10 minutes, until the tomatoes are cooked. Stir frequently so the curry doesn't burn
Season with salt. Add the coconut milk and water and bring to the boil
Lower the heat and allow the curry to simmer with the lid on. Allow it to cook until the gravy thickens, about 20 to 30 minutes.