Arriviste promotes baked food (7)
I believe the answer is:
upstart
'arriviste' is the definition.
(I know that arriviste can be written as upstart)
'promotes baked food' is the wordplay.
'promotes' becomes 'ups' (up can mean to promote or put up).
'baked food' becomes 'tart' (tart is a kind of food. I am not sure about the 'baked' bit.).
'ups'+'tart'='UPSTART'
Can you help me to learn more?
(Other definitions for upstart that I've seen before include "Person who has risen quickly, and arrogant with it" , "Person who behaves arrogantly in the new position" , "Arrogant newcomer" , "Person newly risen from the ranks and arrogant" , "Arrogant Johnny-come-lately" .)