In mixing bowl toss 2 tablespoons olive oil, fennel, onion, parsnips, thyme and crushed red pepper.
Place vegetables on non-stick baking sheet in oven; roast for 15 minutes.
Cook pasta according to package directions; drain, reserving ½ cup pasta water. Return pasta to the pot.
Add remaining olive oil, orange zest and roasted vegetables to pasta and toss well over medium heat until warmed through, approximately 2-3 minutes. Season with salt to taste.
