Roasting pulls the water out of vegetables and
concentrates their flavor. Try tasting a roasted carrot next to a boiled
carrot and you'll see how roasting emphasizes the vegetable's natural
sweetness.
Roasting works best for root
vegetables, such as carrots, turnips, potatoes, onions and for vegetables
that contain a great deal of moisture such as tomatoes and mushrooms. You
can also coat these softer vegetables with bread crumbs to add texture, as
in a gratin.
Sometimes you'll want to roast root vegetables in
their skins like russet potatoes because we like to eat the skins, beets
because they bleed and dry out once they're peeled, and baby vegetables
because their thin skins are entirely edible. But usually we roast
vegetables that have been peeled beforehand. Cut the peeled vegetables
into sections or wedges, or turn them, and then lightly coat with olive
oil or melted butter to prevent them from drying out in the oven.
Vegetables can be roasted alone or in combination.
Most of the time, all you need to do to roast vegetables is to slide them
into the oven and turn them over from time to time so they brown evenly. A
nice touch, however, is to pour a little good meat or chicken broth into
the roasting pan about ten minutes before the vegetables are done. The
broth quickly reduces in the heat of the oven and glazes the vegetables.