Huge Mike prepared ham with Tom (7)
I believe the answer is:
mammoth
'huge' is the definition.
(synonyms)
'mike prepared ham with tom' is the wordplay.
'mike' becomes 'M' (phonetic alphabet: alpha, bravo, charlie etc.).
'prepared' indicates an anagram.
'with' is a charade indicator (letters next to each other).
'ham'+'tom'='hamtom'
'hamtom' anagrammed gives 'ammoth'.
'm'+'ammoth'='MAMMOTH'
(Other definitions for mammoth that I've seen before include "Extinct type of elephant" , "Large 15 animal" , "Gigantic - extinct animal" , "Extinct hairy elephant" , "Extinct shaggy-haired elephant" .)