Dressing chef's starter course involves (5)
I believe the answer is:
patch
'dressing' is the definition.
(both can mean a fabric covering)
'chef's starter course involves' is the wordplay.
'starter' says to take the initial letters.
'course' becomes 'path' (path can mean a route or course).
'involves' is an insertion indicator.
The first letter of 'chefs' is 'c'.
'c' placed into 'path' is 'PATCH'.
(Other definitions for patch that I've seen before include "Plot - piece of cloth - period" , "temporary repair" , "Small piece of ground" , "Covering material" , "Piece of material sewn over a hole" .)