Step 1

Preparation Position 1 rack in center and 1 rack in bottom third of oven and preheat to 400°F. Line 2 rimmed baking sheets with foil. Divide carrots and parsnips between prepared sheets. Sprinkle generously with salt and pepper, then drizzle 3 tablespoons oil over vegetables on each sheet; toss to coat.

Step 2

Roast vegetables 10 minutes; stir. Roast vegetables 10 minutes longer, stir, and reverse sheets. Continue roasting until vegetables are tender and slightly charred, about 15 minutes longer. (Can be prepared 2 hours ahead. Tent with foil and let stand at room temperature. Rewarm uncovered in 350°F oven 10 minutes.)

Step 3

Melt butter in heavy small saucepan over medium heat. Stir in honey and vinegar. Drizzle honey glaze over vegetables and serve.