It called "meggyes piskóta" in Hungarian. It's a (sponge) cake filled with sour cherry. It is a very simple, but very popular cake in Hungary.
I always miss the fresh cherry and sour cherry in winter, but luckily in my family the grandmothers usually bottle fruits for winter. So I have possibility to fill my cake with their delicious bottled fruits :)
My sponge cake recipe you may read here.