Wash the meat and pound it evenly with a meat mallet into one large, flat slice, and season both sides with salt.
For the filling, mix the minced pork with the squeezed roll, the chopped boiled eggs, the raw eggs, salt and pepper until it holds together well.
Spread the filling evenly over one side of the meat, leaving a 2-3 cm border at the edge.
Carefully roll it up tightly, then tie it with kitchen string in 3-4 places so it doesn't open while cooking.
Heat the fat in a larger pan over medium-high heat and brown the roll on all sides for about 8-10 minutes.
Add the chopped onion and the sliced carrots and parsley roots, pour in the water, cover and braise over low heat for 1-1.5 hours, turning now and then and topping up with water.
When the meat is tender, remove the lid and brown it for a few more minutes so it gets a nice colour.
Cut off the string and slice the meat thinly; stir 3 tbsp of sour cream into the gravy, bring to the boil, then pour it over the slices.
Serve with mashed potatoes or pasta.
Based on: A jó házikonyha (a classic Hungarian cookbook), modernised. Calories and protein are estimated.