First cook prawns with 1cup of water for 10 minutes.
Heat oil in a kadai add grated coconut,coriander seeds,red chill i and fry for 2 minutes.
Add chili powder,turmeric powder and coriander powder saute for 2 minutes .
Add small onions to this and saute for 2minutes,until it turns to brown color.Keep it aside.
In another kadai add oil then add onions and green chilies saute for 2 minutes.
Add tomatoes and saute for2 minutes.
Grind the coconut mix in a mixer.
Add this ground mix and cooked prawns to kadai.
Add 1 cup water,tamarind juice and salt to this boil for 2 minutes.
Now nadan chemmeen curry is ready to serve.Serve with rice.