Shellfish local cooked in small pan initially (7)
I believe the answer is:
scallop
'shellfish' is the definition.
(I know that scallop is a type of shellfish)
'local cooked in small pan initially' is the wordplay.
'cooked' is an anagram indicator (letters cooked into a new form).
'in' indicates putting letters inside.
'initially' says to take the initial letters.
The initial letters of 'small pan' is 'sp'.
'local' with letters rearranged gives 'callo'.
'callo' going within 'sp' is 'SCALLOP'.
(Other definitions for scallop that I've seen before include "Shapely dish" , "Bivalve mollusc with fan-shaped shell" , "Shellfish - pilgrim badge" , "one may be in one's shell" , "Bivalve with radiating ridges on shell" .)