Marinate the deveined and washed prawns with 1 tsp salt and ½ tsp turmeric powder. Marinating the prawns for 20 min is enough, but even marinating it for upto an hour is fine.
After finely chopping the clean Mocha florets, immerse the florets in salted turmeric water immediately (1.5 tsp salt and 1 tsp turmeric powder). This is done to prevent discolouration (blackening) of the florets. Soak for three hours.
Drain the water and rinse a few times. Pressure-cook (one whistle) with 1 tsp salt and water just enough to submerge the florets. Open the lid immediately and drain the liquid. (Bonus tip: As this liquid has a lot of nutrients, I add this to various curries like Macher Jhol, Dal, etc.)
When the boiled mocha is cool enough to handle, mash it a bit with hand. Make sure that you don’t mash this finely. We just need some uneven mashing here, so that almost 60% texture is retained.
Meanwhile, heat around 12 tbsp mustard oil. Add the potato, cut into medium-sized cubes. Sprinkle 1 tsp salt while frying. Remove the fried potatoes on a plate, lined with absorbent paper.
In the same oil, fry the coconut until golden in colour. Also fry the raisins until puffed up. Remove in a bowl.
Discard the oil in which the potatoes, raisins and coconut are cooked.
Wash the Kadhai and heat 10 tbsp of mustard oil. Reduce the heat to medium. Now add small batches of marinated prawns to the oil. Fry for 5 min, flipping once. Remove into a bowl.
In the same oil, add the bay leaves, dry red chillies, cinnamon, cloves and green cardamom. Add the cumin seeds. The flame should continue to be at medium.
When the cumin seeds turn brown, reduce the flame and add a paste of turmeric powder, cumin powder, red chilli powder, ginger paste and salt. Sauté continuously until oil separates.
Add the boiled Mocha, fried coconut pieces and fried raisins. Cook on a high flame for 10 min.
Add the potatoes and continue sautéing, until the Mocha releases some oil. At this stage, add the fried prawns (along with some residual liquid/oil that settled at the bottom of the bowl where you kept the fried prawns).
On a medium heat, continue cooking for 10 min. Add sugar, Bengali garam masala powder and slit, green chillies. Cook for 5 min, or until the sugar dissolves. Check for the seasoning. The dish should be slightly on the sweeter side. Adjust salt and sugar accordingly.
Now, mix the ghee properly into Mocha Chingri. Cover the lid and switch off the flame. Open the lid after 15 min and remove the Mocha Chingri into a serving dish. Serve this Bengali delicacy with steamed rice.