To be honest, I'm not totally comfortable recommending Palazzo. It's kinda very unique and, perhaps, could go too much authentic beyond our taste. I didn't enjoy it that much though. But if you wanna experience something real authentic, then this is the one krub.
In fact, if you allow me to broaden the scope of location a bit more, I'd rather recommend something like 'Basilico' at Sukhumvit 33 or Limoncello at Sukhumvit 11. These are the two most favorite Italian restaurants for me krub.
It also depends on what purpose the dinner is for...if you wanna impress someone rather special, probably Audrey Cafe might be the place. It's just CUTEEEE in every way
Don't forget to drop by at After You for a nice dessert too.
Another place just popped up in my head when I'm typing this is the place call 'Witch Tavern'...quite nice na. Located on the Thong Lor street on the side towards Sukhumvit not faraway from Oishi Grand at Thong Lor 10 (So left-hand side if you are driving from Petchburi to Sukhumvit). I've never been there myself but heard tons of people appraising the food there krub.
Sorry to type in English because I'm using a computer in the computer lab at the school
