I live in Budapest and my husband and I LOVE eating at Onyx. We have dinner here about once a quarter to either celebrate something, cheer ourselves up or splash out because we've conjured up some spurious reason to treat ourselves.
This is one of two Michelin restaurants in Budapest (the other being Costes) - and this is the only one that will let you have the vegetarian tasting menu while your companion has a tasting menu with more courses (chef's orders).
We tend to spend about 3 hours at dinner here - it's romantic, the food and wine are amazing and the staff friendly, well-informed and extremely polite and attentive.
Onyx also has a lunch menu, which I would recommend if you want to avoid the higher prices. This daytime menu is not any more expensive than other good restaurants in the area. Just to level-set, Onyx for dinner is exceptionally expensive for Budapest (if you live here and are paid here) but amazing value for money if you're comparing it to Michelin restaurants in other locations.
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