List of dishes chaps start to upgrade (4)
I believe the answer is:
menu
'list of dishes' is the definition.
(I've seen this before)
'chaps start to upgrade' is the wordplay.
'chaps' becomes 'men' (I've seen this before).
'start to' indicates taking the first letters.
The initial letter of 'upgrade' is 'u'.
'men'+'u'='MENU'
(Other definitions for menu that I've seen before include "List of (computer or food) items" , "Options available" , "Bill of fare" , "List of dishes offered by restaurant" , "List of food items on offer" .)