Hot during pleasant recess (5)
I believe the answer is:
niche
'recess' is the definition.
('niche' can be a synonym of 'recess')
'hot during pleasant' is the wordplay.
'hot' becomes 'h'.
'during' means one lot of letters goes inside another.
'pleasant' becomes 'nice' ('nice' is associated in meaning with 'pleasant').
'h' placed into 'nice' is 'NICHE'.
(Other definitions for niche that I've seen before include "Recess - suitable position" , "comfortable situation" , "Small recess or cranny" , "Calling" , "Suitable position (in market, life etc)" .)