De-vein, clean & wash the tiger prawns. Do not discard the heads, you may also keep the skin intact.
Pat the cleaned prawns dry with the help of a paper towel. And smear with a pinch of turmeric powder & salt. Set aside.
Heat half of the mustard oil over medium flame. When the oil is moderately hot gently release the prawns and fry them over medium flame until pink. Set aside once done.
In the same skillet add more oil if need be. When the oil becomes moderately hot throw in the whole garam masala and the bay leaf. Crack the green cardamoms before adding to the oil otherwise they may burst. Allow them to sizzle for a few seconds.
Next, bring down the flame to the lowest setting and allow the oil to cool down a bit (1-2 mins). Gently release the onion paste, stir briskly & fry until the oil oozing state is reached. Increase the flame to medium while frying the onion paste.
Now, add the ginger + green chili paste and saute until the raw smell of the ginger completely disappears.
Add the spices, saute until well roasted, aromatic & oil starts to leave the sides of the pan.
Now add the white poppy seeds paste. Saute until the masalas are well roasted & the poppy seeds paste is fragrant. The masala will become darker, well roasted and very fragrant at this stage.
Add the coconut milk. Stir to mix everything well. Add salt & sugar. Mix well. Cover & simmer for 5 mins at medium low.
Finally, add the shallow fried prawns, cover & simmer for 3-4 mins at low heat.
Serve hot with hot rice. Enjoy!