In which to ship a bighead his breakfast? (5)
I believe the answer is:
boats
'a bighead his breakfast?' is the definition.
The definition suggests a singular noun but the answer is a plural noun.
'in which to ship' is the wordplay.
'in which' becomes 's' (I can't explain this - if you can you should believe this answer much more).
'to' means one lot of letters go next to another (I've seen this in other clues).
'ship' becomes 'boat' (I've seen this before).
's' put after 'boat' is 'BOATS'.
Can you help me to learn more?
(Another definition for boats that I've seen is " Vessels".)