Rasstegai
Rasstegai is a type of Russian pirog with a hole in the top.
History and etymology
The dish was very popular in Tsarist Russia.In rasstegai the filling is not hidden in the dough, and in Russian means "unfastened" pies.
Another version: in Moscow, in the gypsy choir, the beautiful Katya sang very well the Russian song "Sarafanchik-rasstegaychik"; in honor of Katya, rasstegai became a very popular meal in taverns in Moscow.