Polish upper class
The "upper class" of any country is rarely larger than 500 people, many of whom are out of that country at any given time.
If you mean restaurants frequented by the wealthier end of the middle classes (those that live in or near the capital anyway) there are a few. Amaro is popular (and booked solid long in advance). The menu above looks like one of theirs. Basically fusion food with some local ingredients.
This one is an old favourite of the elite. Its official name is Restauracja Belvedere, however the cognoscenti refer to it by another name. Basically classic European international food. Its website is here: belvedere.com.pl/en/home
There's also Fukier, famous in the 90s and 2000s for hair-raising prices, which has become a bit touristy now. Good food though.