1Heat oven to 425°F. In large bowl, toss sweet potatoes, onion, oil, salt and pepper. Arrange potato mixture in single layer in ungreased 17x12-inch half-sheet pan.
2Bake uncovered 25 minutes or until tender. Stir; bake 5 minutes longer.
3In large bowl, mix orange juice and rosemary. Add potato mixture; toss gently to coat.