Ordinary sort of ice cream? (7)
I believe the answer is:
I believe this clue is a double definition.
'ordinary' is the first definition.
(vanilla can mean ordinary or conventional)
'sort of ice cream?' is the second definition.
(Other definitions for vanilla that I've seen before include "Flavouring from pod of certain orchids" , "plant" , "Bland" , "Tasty flavouring for ice-cream" , "type of orchid" .)