They say it takes a genius to describe the obvious, and this may be especially true in vegetarian cuisine. The selection of vegetables to include is less important than the need to have each of the vegetables roughly the same size and thickness, so everything cooks evenly. Prep time is about 5-10 minutes; cooking time is 20-25 minutes, if all the vegetables are roughly the size as a melon-ball.
In any season, it’s a good idea to include bell peppers, which have significant amounts of antioxidants. The green and purple varieties are more tart than the yellow, orange, or red. Moreover, red peppers are extraordinarily high in Vitamin C (more than twice that of a naval orange, in fact).
In winter, a range of selections among sweet potatoes (which have a far greater amount of Vitamin A, as it happens, than their bright orange cousin, the yam), along with beets, Brussels sprouts, parsnips, eggplant, white onions, asparagus and crisp carrots.
In the spring and summer, the selections might be among broccoli, red onion, Roma tomatoes, cauliflower, mushrooms, zucchini, and Fingerling potatoes.
Only the winter squash will need to be peeled prior to cooking, and cut a bit smaller, since it’s quite dense. The asparagus is cut into three, and the lowest part of the stem discarded. For the cauliflower and broccoli, only the florets are added, and red onions are divided into wedges of similar size; as are chunks of zucchini, and Rom tomatoes and mushrooms. If a greater quantity of vegetables is desired, it would be best to prepare them on separate baking sheets, since they must not be too crowded as they roast.
In a large bowl, combine all vegetables with 2-3 tablespoons olive oil to assure that they are completely coated. Then add salt, pepper, a few cloves of minced garlic, or other seasoning you prefer, and some balsamic vinegar or the juice of half a lemon.
Coat the pan with oil or a nonstick spray and arrange the vegetables on the pan(s), taking care that they are in a single layer, so hot air can circulate around each of them.
As a general guide, add 2 cups each of broccoli or cauliflower florets, two cups of squash, 1 zucchini, a handful of mushrooms, 1 large pepper, 1 large onion, 3-4 cloves of garlic, and fresh-ground black pepper and sea salt, to taste.