Description of sea food, cooked then cold (6)
I believe the answer is:
baltic
'description of sea' is the definition.
'Baltic' can be an answer for 'sea' (Baltic is an example). I am not certain of the 'description of' bit.
'food cooked then cold' is the wordplay.
I cannot quite see how this works, but
'food' could be 'balti' (I've seen this before) and 'balti' is found within the answer.
'cold' could be 'c' (eg on taps) and 'c' is located in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for baltic that I've seen before include "Near-landlocked sea of N Europe" , "Almost land-locked sea of Scandinavia" , "Northern European sea" , "cold waters" , "North European sea" .)