Peel and finely dice the onion. Knead minced meat, onion, mustard, egg and breadcrumbs. Season with salt and pepper. Form 4 meatballs from the minced meat mixture
Prepare rice in boiling salted water according to package instructions. Heat the oil in a pan and fry the meatballs for 10-15 minutes while turning. Peel and wash carrots and kohlrabi. Cut carrots lengthwise into quarters, cut kohlrabi into slices. Cook vegetables in salted water for about 6 minutes
Melt the fat in a pot. Sweat flour in it. Deglaze with ⅛ l water and milk. Bring to the boil. Stir in stock and simmer for 3-5 minutes. Season with salt and pepper. Pluck off the chervil leaves, except for something to garnish. Drain vegetables and add to the sauce. Arrange rice, vegetables and meatballs on plates. Sprinkle with chervil and garnish