Puddings rising under pressure (8)
I believe the answer is:
stressed
'under pressure' is the definition.
(I've seen this before)
'puddings rising' is the wordplay.
'puddings' becomes 'desserts' (I've seen this before).
'rising' says the letters should be written backwards (in a down clue, letters go up).
'desserts' written backwards gives 'STRESSED'.
(Other definitions for stressed that I've seen before include "Under great strain" , "Emphasized or strained" , "Emphasised, underlined" , "on edge" , "Insisted" .)