Peel and finely chop the onion. Clean, wash and slice the carrots. Clean, wash and cut leek into rings. Peel, wash and chop the potatoes. Heat 2 tablespoons of oil in a saucepan.
Fry the onion until transparent. Add leek, potatoes and carrots, fry briefly. Sprinkle with sugar. Deglaze with stock, bring to the boil, cover and cook for 20-25 minutes. Mash some of the vegetables.
Season to taste with salt and pepper. In the meantime, form small balls from the ground pork with your hands. Heat 2 tablespoons of oil in a pan and fry the balls for 3-4 minutes, turning them over. Wash parsley, shake dry and cut into fine strips.
Drain the corn in a sieve. Add corn and meatballs to the soup, bring to the boil again and serve sprinkled with parsley.