Sort cranberries, discarding any bruised or decayed fruit. Rinse and drain berries.
In an 8- or 9-inch square baking dish, mix cranberries, sugar, liqueur, and orange peel.
Bake, uncovered, in a 350° regular or convection oven, stirring occasionally, until berries are tender when pierced and juices are syrupy, about 1 hour. Serve warm or cool.
Nutritional analysis per 1/4 cup.