Wash the potatoes and cook in plenty of boiling water for about 20 minutes. Rinse under cold water, drain and peel. Meanwhile clean and wash the Brussels sprouts and cook in boiling salted water for about 15 minutes. Pour the sprouts into a sieve. Melt the fat in a pot. Stir in flour and sweat briefly.
Add 1/4 litre stock and milk while stirring. Bring to the boil, boil for 3-5 minutes and season with salt, pepper and nutmeg. Peel and chop onion. Wash marjoram, shake dry, pluck leaves except for something to garnish from the stems and chop coarsely. Heat oil in a pan and fry minced meat for about 6 minutes while turning it until crumbly. Season with salt, pepper and marjoram. After about 4 minutes add onion. Stir in tomato paste and add 5 tbsp. stock, bring to the boil. Put potatoes, Brussels sprouts and minced meat into an ovenproof dish. Spread sauce over it. Grate cheese coarsely and sprinkle on the casserole.
After about 4 minutes add onion. Stir in tomato paste and add 5 tbsp. stock, bring to the boil. Put potatoes, Brussels sprouts and minced meat into an ovenproof dish. Spread sauce over it. Grate cheese coarsely and sprinkle on the casserole. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 40 minutes. Garnish with marjoram
Preparation time approx. 1 hour 20 minutes