Preheat the 425 degrees. Cut the carrots, parsnips, sweet potato, and butternut squash into 1 to 1 1/4 inch cubes. All the vegetables will shrink while baking, so don't cut them too small.,
Place all the cut vegetables in a single layer on two sheet pans. Drizzle them with the olive oil, salt, and pepper. Toss well. Bake for 25 to 35 minutes until all the vegetables are tender, turning once with a metal spatula.
Sprinkle with parsley, season to taste, and serve hot.