While Budapest still has a sizable Jewish community, there exist only a few kosher restaurants. They're within the old Jewish Quarter, near the Kazinczy Street Orthodox Synagogue. Hanna and Carmel are meat, Kosher Deli and Tel Aviv Café dairy restaurants. If you don't keep strictly kosher, you could also try these Jewish-style, but non-kosher places.
Hanna is a glatt kosher meat restaurant in Budapest's old Jewish Quarter operated by the Hungarian Autonomous Orthodox Jewish Community. Since the restaurant is buried within the fortress-like edifice of the congregation, most locals have never encountered Hanna, even though the surrounding area is currently the center of Budapest's nightlife, teeming with cafés, bars, and restaurants.
The menu comprises both traditional Ashkenazi and Hungarian classics such as matzo ball soup and goulash. Although you can run into an excellent "Jewish" egg salad here — egg spread with onions, goose fat, and goose liver — most dishes are prepared in that typical 1980s Hungarian style where quantity trumps flavor and presentation. Hanna's adorably cranky waiters are also holdouts from a previous generation, but these elements together offer a journey back in time that's worth experiencing.
For the liveliest atmosphere, go for a Friday Sabbath dinner. It's a set four-course meal with complimentary challah bread and Kiddush wine, enlivened by chants of blessings and singing by the orthodox Jewish patrons who come here after the service in the neighboring synagogue. Note that guests must prepay the meal before 2 p.m. on Friday and it costs €30 per person.