Wash the meat, dab dry and cut into strips. Mix buttermilk, 1/2 tsp salt and 1/2 tsp pepper in a large bowl. Add meat and mix in. Leave to stand for about 1 hour.
In the meantime, bring 2.5 litres of water to the boil in a large, wide pot. Add the dumplings, bring to the boil and let it boil over medium heat for about 7 minutes until it becomes bubbly. Pour into a sieve and drain well.
Crumble the pretzel and grind finely in two portions in a universal crusher. Peel, possibly wash and coarsely grate the cubes. Clean, wash and halve the cabbage, cut out the stalk and cut into fine strips. Peel onions and cut into fine rings.
Heat 4 tablespoons of oil in a frying pan, fry the dumplings in two portions in the pan, turning them golden yellow, and remove them. Keep warm. Add another 4 tablespoons of oil to the pan, heat up, add onion rings and fry while turning. Sprinkle with sugar, allow to caramelize slightly, deglaze with vinegar. Stir in mustard, bring to the boil and season to taste with salt and pepper.
Pour the meat into a sieve, drain well and pat dry slightly. Whisk the eggs, 1/2 tsp salt and 1/2 tsp pepper. Turn the meat strips first in the egg and then in the pretzel crumbs. Heat 2-3 tablespoons of oil in a frying pan and fry the meat in two portions over medium heat for about 5 minutes, remove.
Wash parsley, shake dry and chop finely. Mix cabbage, carrots, dumplings, 3/4 of the parsley and vinaigrette. Arrange in a bowl with the chicken strips, sprinkle remaining parsley and garnish with lemon slices as desired. Pretzels taste good with it.