Cook the rice in salted water till just done, drain and run room temperature water through it, drain, keep aside
Heat oil in a non-stick deep pan, add the whole spices followed by the sliced onions and sauté for 4-5 minutes till they turn golden brown
Add the cashew nuts, sugar and a little salt, fry for a while
Add the well-drained rice, mix well but gently
Taste for salt, remove the whole spices and keep aside
Clean and de-vein the prawns, apply half teaspoon of salt and keep for 7-8 minutes, wash off the salt
Apply a little haldi powder to the prawns and keep aside
Heat oil in a non-stick deep pan, add the black cardamom, bay leaf, jeera, sauf and the chopped onions
Sauté till the onions turn golden brown, add the ginger-garlic paste, saute for some time and add the finely chopped or grated tomatoes
When the tomatoes turn pulpy add all the powdered masalas, sauté for about 2 minutes
Mix in the prawns and cook on a low flame for 4 minutes or so, add the chopped coriander and mint leaves, stir well, add some salt, mix
When the prawns are cooked and the gravy is semi-dry add the chopped green chili, mix, taste and adjust seasonings
Add a dash of lime
Grease the base of a flat-bottomed deep glass dish with a little butter, arrange half of the rice at the base
Transfer all the Prawn masala gravy on to the rice layer
Top the gravy layer with remaining rice, dot with a little butter and microwave for 4-5 minutes till it is well heated
Garnish with fried onion barista and wedges of boiled eggs
Serve hot with onion-tomato kachumbar and raita of your choice or with crispy roasted papad