Clean the cauliflower, cut into florets and wash. Cook the cauliflower in boiling salted water for about 15 minutes. Put rice in boiling salted water and let it swell for about 15 minutes. Heat the fat in a pot. Sweat flour in it.
Deglaze with milk and 1/4 litre cauliflower water while stirring. Add mustard and stock, season with salt and pepper and simmer at low heat for about 5 minutes. Cut sausage into thick slices. Heat oil in a pan. Fry slices of bratwurst in it for about 4 minutes. Wash the chives and cut into small rolls. Pour cauliflower on a sieve. Add bratwurst and cauliflower to the sauce. Sprinkle with chives.
Wash the chives and cut into small rolls. Pour cauliflower on a sieve. Add bratwurst and cauliflower to the sauce. Sprinkle with chives. Pour rice on a sieve and drain. Serve the rice with the ragout