Hot drink with marshmallows (5)
I believe the answer is:
cocoa
'hot drink with marshmallows' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for cocoa that I've seen before include "Bean used in making chocolate" , "Chocolate powder" , "drink from beans" , "Hot chocolate drink" , "Powdered cacao seeds" .)