Preheat oven to 450°F. Toss parsnips with oil and salt to taste in a shallow (1-inch-deep) baking pan and roast in middle of oven, turning over halfway through cooking, until golden and tender, 30 to 35 minutes total.oss parsnips with oil and salt to taste in a shallow (1-inch-deep) baking pan and roast in middle of oven, turning over halfway through cooking, until golden and tender, 30 to 35 minutes total.