It might be used to fry prawns every now and then (3)
I believe the answer is:
pan
'it might be used to fry' is the definition.
The definition suggests a singular noun which matches the answer.
'prawns every now and then' is the wordplay.
'every now and then' indicates alternate letters (letters selected at regular intervals).
The alternating letters of 'prawns' are 'PAN'.
Can you help me to learn more?
(Other definitions for pan that I've seen before include "A vessel; criticise strongly" , "Try to find gold" , "Swing" , "Cooking container; god" , "Wash gravel" .)