Side order of cream in tea taken occasionally? (5)
I believe the answer is:
raita
'side order' is the definition.
(I've seen this before)
'cream in tea taken occasionally?' is the wordplay.
'taken occasionally?' means one should take alternating letters.
'cream'+'in'+'tea'='creamintea'
The alternating letters of 'creamintea' are 'RAITA'.
'of' is the link.
(Other definitions for raita that I've seen before include "dish in the curry house" , "Dishy thing" , "condiment from India" , "Indian dish of chopped cucumber and yoghurt" , "food dish" .)