Some popular variety of grub (5)
I believe the answer is:
larva
'grub' is the definition.
(I've seen this before)
'some popular variety of' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'LARVA' is hidden within 'popular variety of'.
(Other definitions for larva that I've seen before include "Insect's immature form" , "Wriggler" , "Worm-like insect before metamorphosis" , "Immature form of an insect before metamorphosis" , "Early stage of creature" .)