Peel and halve the shallots. Wash the legs and pat dry. Heat 2 tablespoons of oil in a large frying pan with lid. Brown the legs in it. Season with salt and pepper and remove.
Sauté the shallots in the hot frying fat. Add bay leaf and fry briefly. Stir in the whole mustard. Deglaze with 600 ml water and cream, bring to the boil. Add legs and braise covered on the stove for about 1 1⁄4 hours.
Wash the potatoes thoroughly and cut in half. Wash the rosemary, shake dry, pluck needles from the stems. Mix rosemary, 1 teaspoon salt, 1⁄2 teaspoon pepper, potatoes and 2 tablespoons oil well. Spread on a baking tray and bake in a hot oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer) for approx. 45 minutes
Lift the legs out of the stock. Keep warm. Stir starch and a little water until smooth. Stir the starch into the stock, bring to the boil and simmer for about 3 minutes. Season the sauce with salt and pepper. Serve everything.
Fry the legs in a large roasting pan for about 5 minutes on each side until golden brown. These roasting substances form the basis for a delicious sauce