Rinse lemons hot and grate them dry. Peel the peel with a zest ripper and set aside covered. Halve the lemons and squeeze the juice from one half. Peel onion and parsnips. Wash the parsnips. Dice onion and parsnips. Heat butter. Sauté onion cubes in it. Add the parsnips and fry briefly. Deglaze with broth, season with salt, pepper and 2 tbsp. lemon juice. Cover and cook for about 30 minutes.
Heat the oil in a frying pan. Stir-fry the minced meat for about 5 minutes until crumbly. Season with salt and pepper. Wash the oregano, dab dry and remove the leaves
Finely puree the soup and pass it through a sieve into a pot. Mix crème fraîche with milk and add to the soup. Season to taste with salt, pepper, lemon juice and sugar. Arrange the soup with minced meat in bowls, sprinkle with lemon peel and oregano