Spicy food pioneer cooked, keeping very quiet (9)
I believe the answer is:
pepperoni
'spicy food' is the definition.
(I've seen this before)
'pioneer cooked keeping very quiet' is the wordplay.
'cooked' is an anagram indicator.
'keeping' means one lot of letters goes inside another.
'very quiet' becomes 'pp'.
'pioneer' with letters rearranged gives 'peeroni'.
'peeroni' enclosing 'pp' is 'PEPPERONI'.
(Other definitions for pepperoni that I've seen before include "what may be called a banger" , "Highly-seasoned sausage" , "Butterfly-attracting shrub" , "Spicy Italian sausage" , "Seasoned beef/pork sausage" .)