Bring 250 ml water, butter and milk to the boil. Fold in the corn semolina with a whisk and let it swell for 4 minutes while stirring. Chop the walnuts. Remove semolina from the stove, knead in parmesan, egg yolk, walnuts and rosemary. Season with salt and nutmeg and form into small dumplings.
Remove fat and tendons from the duck breast and cut the skin with a sharp knife in a diamond shape. Place in a cold pan without fat and fry slowly on the skin side for 10 minutes. Turn and fry for another 3 minutes. Season with salt and pepper on both sides. Cook in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 8 minutes. Add duck stock to the pan, reduce a little, add jelly and cranberries. Continue cooking for 5 minutes. Mix starch with 2 tablespoons of water and thicken the sauce, bring to the boil again. Remove duck breast from the oven and keep warm. Add gravy to the sauce, season to taste with salt and pepper.
Continue cooking for 5 minutes. Mix starch with 2 tablespoons of water and thicken the sauce, bring to the boil again. Remove duck breast from the oven and keep warm. Add gravy to the sauce, season to taste with salt and pepper. Heat 1 tablespoon of olive oil in a frying pan and fry the dumplings all around. Cut the duck breast into slices and serve with the sauce and the dumplings. Garnish with walnuts and rosemary