In the same building where you can find Gerbeaud, you can also find a very nice and elegant restaurant, Onyx. They serve delicious food, in a very nice environment. The price are not the lowest, but you can find more expensive restaurant as well around town. Be sure to notice that the entrance to Onyx is from the Harmincad Street.
Onyx Restaurant Budapest
Address: 1051 Budapest, Vörösmarty Tér 7-8
Metro stop: Vörösmarty Tér (yellow metro)