it's very simple, you just get one of those round buns, like a giant burger bun (they are called lepinja in serbian), you need some grease and meat juice from frying up some meat, salt, lightly mixed egg, and then bake it gently in an oven so the top gets crunchy as well and the egg all sets, and that's it

i ate one made by a guy from the most famous town where this dish originated, Uzhitse (uzice) southwest of belgrade, near the main road towards sarajevo. i felt like superman after eating it. fantastic for a rakija hangover lol