Pound the beef slices till they are quite thin. Salt and pepper them, and put them aside.
Cut bacon into small dice and render it in a frying pan. Add 1 minced onion and brown it fast.
Add lecsó. Stir and cook for another few minutes.
Beat eggs and 1tablespoon of the flour until slightly thickened. Add to bacon and lecsó to make the filling.
Place 1tablespoon of filling on each beef slice, or more depending on the size of slices, and press it down hard. Try to fold the sides over and then roll each side to a tube shape. Tie the rolls with string.
Melt lard in a heavy pot. When hot, add beef rolls and brown in a 500°F. oven for 15 minutes.
Remove beef rolls from the pot and reduce heat to 300°F.
Put the second minced onion in the pot and brown it fast. Add diced green pepper and tomato, the paprika and tomato purée. Stir well.
Replace beef rolls in the pot and add water to barely cover meat. Cover the pot and cook the meat slowly either in the oven or on top of the stove for about 1 hour, or until done.
Mix sour cream and remaining 1tablespoon flour. Add this to the sauce and mix well. Cook it over very low heat for another 10 minutes.
Place beef rolls in the center of a platter and pour sauce on top. Serve with buttered Egg Dumplings.