Clean the Brussels sprouts and carve the stalk crosswise. Cut the sprouts in half and cook in boiling salted water for about 6 minutes. Take them out and let them drip off. In the meantime, place the croquettes on a baking tray and bake in a preheated oven (electric range: 225 °C/ gas: level 4) for 20-25 minutes.
Meanwhile wash the pork fillets, dab dry and season with salt and pepper. Heat the oil in a pan and fry the pork fillets in it, covered, at medium heat for about 10 minutes.
In the meantime, clean and slice the mushrooms. Remove pork fillets from the pan and keep warm. Wash and quarter the tomatoes and remove the seeds. Cut the flesh into medium sized cubes.
Peel and finely chop the onion. Heat the fat in a pot and sauté the onion in it. Add the Brussels sprouts and heat them covered for about 5 minutes at medium heat. Season with salt, pepper and nutmeg.
In the meantime, sauté the mushrooms in the cooking fat and deglaze with white wine, stock and cream. Bring to the boil. Stir cornflour with 1 tablespoon of water until smooth and thicken the sauce. Season with salt and pepper.
Coarsely crush colored pepper and sprinkle on the pork fillets. Add the diced tomatoes to the Brussels sprouts. Cut pork fillets into thick slices as desired, arrange on plates with Brussels sprouts, mushroom sauce and croquettes.
Garnish with parsley.