Clean broccoli, cut into florets from the stalk and wash. Peel, wash and slice the carrots. Blanch vegetables in boiling salted water for about 4 minutes. Wash the meat, dab dry and season with salt and pepper.
Heat the oil in a frying pan. Sauté the meat in it for about 1 minute on each side. Melt the fat in a pot. Sauté the flour in it. Add stock and milk while stirring, bring to the boil and simmer for about 4 minutes.
Season with mustard, salt and sugar. Layer meat, vegetables and sauce in a greased casserole dish. Sprinkle with cheese. Gratinate in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 20 minutes.