Peel the onions, cut into small cubes. Whisk the minced meat with pickling salt and pepper, fill into preserving jars.
Fill the grease pan of the oven 1 cm high with water. Close the jars, place them in the water and cover with wet paper. Place the fat trays in the lowest rack of the oven and cook at 180 °C for a little 1 1/2 hours.
rinse thoroughly in hot water with the addition of a commercial detergent, rinse in clean water. Put the jars on a dish rack and drain. Put the preserving rings in clear water for a few minutes, then put them in fresh water until use. Fill the jars about 3/4 full with the meat mixture. Place rubber ring and lid on the cleaned jar rim while still wet.
If canning jars are sealed with spring or possibly bail, make sure rubber rings do not shift. To take advantage of the proper heat in the oven, place 6 jars each of the same size and contents, without touching, in the grease trap filled 1 cm high with water. Cover the jars with a layer of wet paper and place the grease trap as far down in the oven as possible.