Peel the shallots and garlic. Dice shallots finely, chop garlic. Heat the fat in a pot and sauté the shallots and garlic. Add chestnuts, roast them slightly, deglaze with port wine.
Add the stock and 300 g cream, bring to the boil. Cover and let simmer at medium heat for about 5 minutes.
Wash the chives, shake dry and chop coarsely. Whip 100 g cream until semi-stiff and chill. Puree soup finely, season with salt and pepper. Arrange in deep plates, spread cream and goose breast on top and sprinkle with chives.