Roll a companion leaves on plate? (7)
I believe the answer is:
spinach
'leaves on plate?' is the definition.
(I've seen this before)
'roll a companion' is the wordplay.
'roll' becomes 'spin' (spin is a kind of roll**).
'companion' becomes 'ch' (I've seen this in other clues).
'spin'+'a'+'ch'='SPINACH'
(Other definitions for spinach that I've seen before include "Vegetable plant" , "Blackboard stand" , "leaves on plate?" , "Vegetable, source of iron" , "Popeye's vegetable" .)