Sort cranberries and discard any soft or spoiled ones. Rinse and drain berries.
Mix cranberries, sugar, brandy, and orange peel in an 8- or 9-inch square baking dish. Bake, uncovered, in a 325° oven until berries are tender when pierced and most of the liquid has evaporated, about 1 hour, stirring occasionally. Serve warm or cool.