Peel and finely dice the onion and garlic. Clean, wash and chop the zucchini. Peel, wash and chop the potatoes. Simmer everything in 1/2 l water covered with broth for about 20 minutes.
Meanwhile knead the minced meat, curd and breadcrumbs. Season with salt and pepper. Form small balls from the mixture with moistened hands. Heat the oil in a pan. Fry the meatballs for about 5 minutes, turning them over.
Wash parsley, shake dry and chop. Remove 2-3 tbsp. of vegetable pieces from the soup. Briefly puree the remaining vegetables in the broth with a hand blender. Season to taste with salt, pepper and lemon juice.
Add the vegetable pieces and meatballs to the soup, warm up again if necessary. Sprinkle with parsley.