Step 1Heat the oven to 475 degrees.
Step 2Scatter the parsnips, carrots, onions, garlic and thyme sprigs in the bottom of a large roasting pan or baking dish. Drizzle the vegetables with 2 tablespoons of the oil and sprinkle generously with salt and pepper.
Step 3Lay the chicken pieces on top of the vegetables. Drizzle the remaining 2 tablespoons oil over the chicken, rubbing it in to coat all sides, then sprinkle with salt and pepper. Roast for 25 minutes.
Step 4Meanwhile, in a small bowl, whisk together the lemon juice, honey and chopped thyme until combined.
Step 5Reduce the oven temperature to 400 degrees. Brush the chicken evenly with the lemon-honey mixture, then continue cooking until the skin is browned, the juices run clear, and an instant-read thermometer inserted into the thickest part of a thigh registers 165 degrees, 25 to 30 minutes longer. Let rest for 10 to 15 minutes before serving.