Italian mounting show with extravagant sculpture etc. (9)
I believe the answer is:
trattoria
'italian' is the definition.
(Italian restaurant)
'mounting show with extravagant sculpture etc' is the wordplay.
'mounting' is a reversal indicator (going up in a down clue).
'show' becomes 'air' (both can mean broadcast).
'with' says to put letters next to each other.
'extravagant' becomes 'OTT' (short for over the top).
'sculpture etc' becomes 'art' (sculpture is an art).
'air'+'ott'+'art'='airottart'
'airottart' backwards is 'TRATTORIA'.
(Other definitions for trattoria that I've seen before include "Italian restaurant" , "Place to eat" , "Italian eating establishment" , "where Italians eat" .)