For the duchess potatoes, wash the potatoes and boil them in boiling water for about 25 minutes. Wash the turkey meat, dab dry and cut into cubes. Heat the oil in a pot. Fry the meat in it in portions until golden brown, season with salt and pepper and remove.
Drain the carrots on a sieve. Clean, wash and halve the mushrooms. Sauté in cooking fat and remove. Put the fat in the pan, melt. Add flour and sweat in it. Deglaze with stock and crème fraîche and bring to the boil.
Add meat, mushrooms, peas and carrots and simmer for about 5 minutes. Season to taste with mustard, salt and pepper. Drain the potatoes, peel and mash them with a potato masher, season with salt and add the milk.
Process everything into a solid mass. Pour the puree into a piping bag with a star-shaped spout and squirt small heaps in a spiral shape onto a baking tray. Melt butter and sprinkle the potato spirals with it.
Bake in the preheated oven (electric: 225 ° C/ gas: level 4) for about 5 minutes. Wash the parsley and chop, except for something to garnish. Sprinkle parsley over the ragout. Arrange turkey ragout and duchess potatoes on plates and garnish with parsley.