Heat oven to 350°F. Place turkey breast in ungreased 13x9-inch (3-quart) baking dish. Arrange sweet potatoes, cranberries and onions around turkey. Pour orange juice over top. Sprinkle with marjoram and salt. Cover with foil.
Bake at 350°F. for 1 hour. Uncover; brush with melted butter. Bake an additional 30 minutes or until turkey is fork-tender and juices run clear, spooning pan juices over turkey and vegetables once during baking. Serve turkey and vegetables with pan juices.