Pound the top round slices thin with a meat mallet, and season both sides with salt and pepper.
Squeeze out the soaked bread roll, crumble it, and mix it with the minced pork, the egg, the finely chopped onion and the parsley, seasoning with salt and pepper.
Place equal portions of the filling in the middle of each piece of meat, roll up, and tie with string or secure with toothpicks so it doesn't open during cooking.
Preheat the oven to 180°C.
Heat the fat in a pan, and brown the meat rolls all over to get a nice crust.
Arrange them in a greased roasting tin, pour in half the beef stock, and put in the oven; roast for 45-50 minutes, basting occasionally with the pan juices.
If the juices in the tin dry up, top up with the remaining beef stock.
At the end of roasting, thicken the pan juices with a little flour mixed with water, and serve with the sliced meat.
Based on: Malatinszky Fanny szakácskönyve (a classic Hungarian cookbook), modernised. Calories and protein are estimated.