Roasted Fennel, Carrots and Red Onion

This recipe comes from The Complete Italian Vegetarian Cookbook by Jack Bishop. 

1 large fennel bulb (about one-and-a-half pounds)
1 medium red onion, cut into 8 wedges
2 medium carrots, peeled, halved lengthwise and cut into 2-inch lengths
2 Tbsp extra-virgin olive oil
salt
1 Tbsp aged balsamic vinegar

Preheat the oven to 425 degrees.
Trim and discard the stems and fronds from the fennel. Remove any tough or blemished outer layers and the core. Cut into several long slices that are about 1/2" thick.
Toss the vegetables with oil and season generously with salt. Place in roasting pan.
Roast for 30 minutes, turning once after 20 minutes.
Drizzle the vinegar over the vegetables and toss gently.
Roast 5 minutes more.