Hippies' food (3)
I believe the answer is:
'food' is the definition.
(pie is a kind of food)
'hippies'' is the wordplay.
'PIE' is hidden in amongst the letters.
However, I am not sure how this is indicated.
Can you help me to learn more?
(Other definitions for pie that I've seen before include "Confused, mixed type" , "Type of chart" , "Pastry-crust savoury" , "Pecan or blueberry dish?" , "welcome luxury" .)