Finely chop the apple, onion and bacon (brisket) and fry in turn on the fat from the brisket. Beat the remaining duck breasts and salted lard in a blender in pulse mode, without bringing it to the consistency of paste. Add the fried apples, onions and brisket. Whisk again until a homogeneous consistency is obtained. Fry the flour in butter, whisk it with cream until thickened. Beat in the egg, boil until thickened. Add this bechamel sauce to the minced meat.