Cook and bring up after the start of the banquet (6)
I believe the answer is:
braise
'cook' is the definition.
(I know that braise is a more specific form of the action cook)
'bring up after the start of the banquet' is the wordplay.
'bring up' becomes 'raise' (raising is a kind of bringing up).
'after' means one lot of letters go next to another.
'the start of' says to take the initial letters.
The initial letter of 'banquet' is 'b'.
'raise' put after 'b' is 'BRAISE'.
'and' acts as a link.
(Other definitions for braise that I've seen before include "Cook by stewing" , "13 across (anag)" , "Re bias (anag.)" , "Fry then stew slowly" , "Cook or stew slowly" .)