Italian wine bar stocking the ultimate in Prosecco (5)
I believe the answer is:
soave
'italian wine' is the definition.
(I've seen this in another clue)
'bar stocking the ultimate in prosecco' is the wordplay.
'bar' becomes 'save' (both can mean 'except').
'stocking' means one lot of letters goes inside another ('stock' can mean 'carry' or 'contain').
'the ultimate in' suggests the final letters (take the ultimate ie last letter).
The last letter of 'prosecco' is 'o'.
'save' placed around 'o' is 'SOAVE'.
(Other definitions for soave that I've seen before include "White wine from NE Italy" , "Dry white wine from Verona" , "Italian dry white wine" , "Italian wine region" , "Drink" .)