Peel the potatoes, slice the kohlrabi, then cut into sticks, add to the boiling vegetable stock, cook for 15 minutes.
In the meantime, peel the carrots and cut them into sticks, cook them in separate salted water until they are firm to the bite.
Season the ground beef with salt, pepper, chives and parsley. Shape into small, bite-sized balls and fry them.
Remove the saucepan with the vegetable stock from the heat, remove half of the vegetables and set aside. Puree the broth with the remaining vegetables with the hand blender and whip until frothy. Season with salt, pepper, the herb sour cream and a little nutmeg. Now add the firm carrots, kohlrabi, potatoes and the meatballs and bring back to eating temperature. Serve sprinkled with chopped parsley.