Mix the minced beef, veal, eggs, breadcrumbs, shallots and herbs, season with the meat seasoning. Knead until the mixture is compact and homogeneous. Divide the meat mixture into 8 portions and shape into spheres. Mix the spinach, ricotta, Parmesan and egg yolk thoroughly, season with salt and pepper. Oil the Burger Press well, place a meat ball inside and press briefly, make an indent with a soup spoon and lay the bacon on top. Add a quarter of the spinach/cheese mixture and push the bacon down into the centre. Place a second ball of meat on top and press it down firmly.