Preheat oven to 425℉/220℃. Line a heavy baking tray with unbleached parchment paper.
Prep veggies: peel parsnips and carrots and cut lengthwise into ¼" strips. Thinly slice onion. Cut oranges in half through the stem and then cut into ¼" thick half moons.
In a medium sized bowl, toss cut veggies in olive oil, honey, salt and pepper. Mix until evenly coated.
Turn veggies onto prepared baking pan. Spread evenly and then add the sprigs of fresh thyme on top.
Roast in preheated oven for 35 minutes, mixing once half way through.
Remove thyme stems and transfer to serving platter or bowl. Sprinkle on some chopped fresh parsley or fresh thyme leaves if desired.