Trattoria frozen dessert (7)
I believe the answer is:
granita
'trattoria frozen dessert' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for granita that I've seen before include "Crushed ice drink" , "Kind of water ice - a rag tin (anag)" , "Grainy flavoured water ice - Riga ant (anag)" , "Italian water ice" , "type of sorbet" .)