Wash the potatoes thoroughly and cook in boiling water for 25-30 minutes. Wash marjoram, dab dry, put 4 stems aside for garnishing. Pluck the remaining leaves from the stems. Wash and peel the carrots. Clean and wash the leek. Peel and wash celery.
Peel onion. Cut vegetables into fine cubes. Heat oil in a pan. Fry the minced meat for 5 minutes while turning, frying the diced vegetables for the last 2 minutes. Stir in tomato paste and sweat for 1 minute while stirring. Douse with red wine. Reduce the liquid halfway down while stirring and mix in the tomato cubes. Season with salt, pepper and marjoram. Drain the potatoes, cut the long side to the middle and press them apart. Fill with bolognese sauce. Grate cheese and sprinkle over potatoes.
Douse with red wine. Reduce the liquid halfway down while stirring and mix in the tomato cubes. Season with salt, pepper and marjoram. Drain the potatoes, cut the long side to the middle and press them apart. Fill with bolognese sauce. Grate cheese and sprinkle over potatoes. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 10 minutes. Arrange in portions and garnish with marjoram