Some prawn facts are shared in the NOTES below, read them. Begin by washing and cleaning the prawns well. Remove the skins, de vein them and keep the tail intact. I used cleaned, de veined frozen colossal prawns with heads removed. So, I just removed the skins and washed them a few times under running tap water. However, you may keep the shells intact.
Bhapa Chngri needs to be steamed so you need to gather a stainless stell tiffin box with a secure lid.
In the tiffin box add the mustard paste, poppy paste, coconut milk, turmeric powder, salt to taste and mix every well until a smooth slurry forms.
Add the prawns into the slurry. Mix together to coat the prawns well.
Next, layer 1/2 of the mentioned grated coconut and pour mustard oil on top of the coated prawns. Gently mix everything.
Layer the remaining grated coconut and throw in the rest of the green chilis. Secure the lid of the tiffin box. It's ready for steaming.
Pour 2 cups water in the inner pot of the Instant Pot and place the steel trivet inside the inner pot. Gently place the tiffing box. Close the lid of the Instant Pot, seal the valve and PRESSURE COOK on HIGH for 6 mins.
After 6 mins when the Instant Pot begins to beep. Wait for Natural pressure release for 6 mins and than release the rest of the pressure manually by moving the valve from the SEALING to the VENTING position.
Open the lid carefully, allow the hot water to cool down a bit, the trivet is very hot at this stage. Once the steam has escaped from the hot water. Carefully bring out the trivet along with the tiffin box.
Open the lid of the tiiffin box, drizzle some more mustard oil on top of the Chingri Bhapa and enjoy it with some white hot rice.