Heat oven to 375° F. In a large bowl, toss the parsnips, carrots, oil, sage, 1 teaspoon salt, and 1/2 teaspoon pepper. Spread on a rimmed baking sheet and roast, stirring twice, until the vegetables are golden, 45 to 55 minutes. Make-Ahead Tip: Peel and cut the parsnips and carrots, wrap in a damp paper towel, and refrigerate in a resealable container or bag for up to 1 day.