Wash the turkey breast, dab dry and cut into strips. Cook the Brussels sprouts in boiling salted water for about 10 minutes, remove and drain. Halve the sprouts. Halve chestnuts. Wash marjoram, dab dry and pluck leaves from the stalks.
Peel and finely dice the shallots.
Wash the potatoes thoroughly, peel the beetroot. Cut both into slices and mix with 2 tablespoons of olive oil, season with salt and pepper. Brush a baking tray with 1 tablespoon of olive oil and spread vegetable slices on top.
Cook in the preheated oven (electric cooker: 200 °C/ circulating air: 175 °C/ gas: see manufacturer) for 20-25 minutes.
Heat 1 tablespoon sunflower oil and icing sugar in a frying pan. Add the Brussels sprouts and chestnuts and caramelise while stirring. Remove and set aside. Wipe out the pan. Heat 2 tablespoons of sunflower oil in it and fry the turkey breast while turning it.
Add the diced shallots and fry them. Deglaze with white wine and cream. Simmer at medium heat for about 10 minutes, season with salt and pepper. Shortly before the end of the cooking time add Brussels sprouts and chestnuts.
Arrange shredded meat and vegetables on plates and sprinkle with marjoram.