Wash the Jerusalem artichokes and cook in boiling water for about 15 minutes. Bring stock, vinegar, 1-2 tsp. mustard and 3 tbsp. oil to the boil, season with salt and pepper. Let simmer for about 3 minutes. Drain the Jerusalem artichoke, rinse briefly under cold water and cut in half.
Heat 2 tablespoons of oil in a large frying pan, fry the tubers for about 3 minutes while turning. Remove and season with salt and pepper. Pour hot marinade over the Jerusalem artichokes and let it stand for at least 30 minutes.
Meanwhile, boil 2 eggs in boiling water for about 8 minutes, remove them and rinse with cold water. Soak the rolls. Finely chop the garlic. Peel 1 onion and chop finely. Knead minced, squeezed roll, onion, garlic, 1 teaspoon salt, paprika, 1 teaspoon mustard, Italian herbs, 1 egg and pepper.
Form approx. 12 meatballs from the chopped mass. Heat 2 tablespoons of oil in a frying pan and fry the meatballs for 8-10 minutes over medium heat, turning them over. Remove and keep warm. Peel 1 onion and cut into slices.
Cut the cucumbers into thin slices. Coarsely chop the eggs. Carefully fold the onion, cucumber slices and eggs into the Jerusalem Artichoke Salad. Arrange salad and meatballs on plates.