Hot stuff assembled for the audience? (7)
I believe the answer is:
mustard
'hot stuff' is the definition.
'assembled for the audience?' is the wordplay.
'assembled' becomes 'mustered' (I've seen this before).
'for the audience?' indicates a 'sounds like' (homophone) clue (I've seen 'for the audience' mean this).
'mustered' sounds like 'MUSTARD'.
(Other definitions for mustard that I've seen before include "Powdered seeds used to make condiment" , "Hot-tasting condiment" , "Yellow sauce" , "Dark yellow" , "Pungent powder or paste" .)