For preparing nadan chemmeen fry, first clean and de-vein prawns by making a small slit on top and remove the vein with a knife. Wash well and allow it to drain. Meanwhile grind onion and dry red chillies without water.
Mix onion paste, turmeric, fish masala, gram flour and salt. Make a thick batter.
Marinate shrimps in it for 30 minutes.
Deep fry it in oil. When half done, add chopped garlic, green chillies and curry leaves. Fry for a few more minutes till crisp.
Do not stir continuously, as the masala coating will be separated.