Heat oven to 400°F. Cut peeled squash in half lengthwise; remove and discard seeds. Cut each half in half lengthwise, and cut into 1/2-inch slices. In large bowl, place squash, sweet potato and onion. Drizzle with oil; sprinkle with garam masala, cumin and salt. Stir until evenly coated. Arrange on ungreased 15x10x1-inch pan. Bake 15 minutes; stir. Bake 15 to 20 minutes longer or until vegetables are tender.