Soup served in club or school (6)
I believe the answer is:
borsch
'soup' is the definition.
(borsch is a kind of soup)
'in club or school' is the wordplay.
'in' indicates the answer is hidden within the clue.
'BORSCH' can be found hidden inside 'club or school'.
'served' acts as a link.
(Other definitions for borsch that I've seen before include "Soup made with beetroot" , "Russian or Polish soup usually containing beet juice" , "Russian beetroot soup" .)