Marinate the lobsters (or jumbo prawns) for atleast 15 min, with turmeric powder and salt.Heat oil in a kadai or a pan. When it starts smoking, reduce the flame to medium and introduce the lobsters carefully and close the lid immediately to prevent sputtering. After 1 min, turn the lobsters and fry the other side for another minute. Remove the lobsters from the oil.In the same hot oil, add the bay leaf, whole cinnamon (cassia bark), green cardamoms and wait for a few seconds. Add the cumin seeds and let these seeds turn light brown. Add the chopped onion and half the salt (for the curry). Sauté for 7 min, or until the onion looks golden-brown and soft.Add the turmeric and the cumin powders, combined with 4 tbsp water. Sauté continuouslyto prevent burning of the powders. Add the ginger paste and sauté again, sprinkling a little water if the onion mixture starts sticking to the pan. After 5 min, add the rest of the salt, sugar, red chilli powder, black-mustard-seed paste, raisin paste and coconut paste and sauté till the mixture starts separating from the oil.At this stage, add the fried lobsters and sauté for 5 min at a simmered flame. Add whole green chillies and ¾ cup of water. Let the curry boil for 10 min, simmered and covered. Before serving, add the ghee to the curry.