Peel the potatoes, wash them, put them in a pot, add wine and stock and cook in a closed pot for about 20 minutes. For the sauce melt fat in a pot, dust with flour and sauté briefly while stirring. Coarsely grate cheese
Drain the finished potatoes and collect the cooking liquid. Measure out 800 ml cooking liquid and pour it into the roux while stirring. Bring to the boil and simmer for about 5 minutes. Season to taste with salt, pepper and mace. Add half the cheese and melt in the hot sauce
Place the potatoes and sauce in a greased casserole dish. Sprinkle with remaining cheese. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for approx. 30 minutes