Stirred hot ingredient of some teas (7)
I believe the answer is:
rosehip
'ingredient of some teas' is the definition.
(ingredient in rose teas)
'stirred hot' is the wordplay.
'stirred' becomes 'rose' (stir can mean to rise or wake up).
'hot' becomes 'hip' (both can mean fashionable or trendy).
'rose'+'hip'='ROSEHIP'
(Other definitions for rosehip that I've seen before include "Fruit of flower used for syrup" , "Hedgerow or garden fruit" , "Fruit on wild plant" , "Berry for syrup" , "Part of plant" .)