Piece of bread and a tin containing European crayfish, perhaps (10)
I believe the answer is:
crustacean
'crayfish perhaps' is the definition.
(crayfish is a kind of crustacean)
'piece of bread and a tin containing european' is the wordplay.
'piece of bread' becomes 'crust' (bread has a crust).
'and' says to put letters next to each other.
'tin' becomes 'can' (synonyms).
'containing' is an insertion indicator.
'european' becomes 'E' (abbreviation e.g. EU).
'can' placed around 'e' is 'cean'.
'crust'+'a'+'cean'='CRUSTACEAN'
(Other definitions for crustacean that I've seen before include "crab, for example?" , "Hard-shelled arthropod" , "Lobster perhaps" , "seafood" , "Creature like a shrimp or lobster" .)