Cut squash in half lengthwise, and remove seeds; set aside. Wash cranberries and drain. Combine cranberries and remaining ingredients, tossing lightly.
Spoon cranberry mixture evenly into squash halves. Place in a 13- x 9- x 2-inch baking dish, and add 1/2 inch water. Bake, uncovered, at 350° for 1 hour and 20 minutes.