my mother used to make these and i honestly can't remember if she used ground beef or not but for some reason, it doesnt sound right to me. then makes me wonder what kind of meat she used for the hamburger patties and what she put in them. they were small, about the size of my palm when cooked and we didn't put them in buns. it was just for eating with rice and banchan basically.
oh yea i think its called Yuk Sanju Chunyua. i could be wrong