Grind together 1/2 grated coconut ,10-12 roasted red chillies ,small piece of tamarind into a smooth paste .
add enough water to the paste to make it to gravy consistency.
add salt to taste ,prawns and keep it to boil.
after one boil reduce flame and simmer for 5 min.
now add hing dissolved in water or powder.
simmer for 1 more min,
then add 1tsp of coconut oil and
switch off flame..... Gassi ready