The owners of the establishment make theirs a bit differently than my mother does. They covered a thick piece of meat with even thicker dough. Sort of like this picture.
My mom uses ground meat and a thin piece of dough with various spices. We enjoy it with a combo of sweet paprika and a plain yogurt drink. My mom also makes potato with onion, as well as cheese Piroshki. Of course the Russian Hamburger was just a gimmick to attract customers because what American doesn't love a burger. OK I guess their are a good deal of folks who may not. But I just wanted to clarify what a Piroshki actually is. Try it though Piroshki's are quite delicious.