Rinse the goose, dry it and rub it with salt on the outside and salt and pepper on the inside. Put it in a large roasting pan, pour a quarter of a liter of warm water and add the peeled onions cut in half. Roast the goose for about 2 to 3 hours, turning frequently and baste with the dripping fat, in the oven at 200 degrees – lower/middle rack.
Half an hour before the end of the roasting time, degrease the sauce and brush the goose with beer to make the skin nice and crispy. Remove the goose from the sauce, season the sauce and thicken it with maizena (cornstarch) mixed in cold water. Cut the goose into pieces, serve the sauce separately and bring everything to the table together with potato dumplings.