Outdoor grilling is great for meats and fish, but grilling most vegetables can be a problem.
Put them on the grate and they tend to fall through into the fire; put them on skewers and some parts will burn while others steam.
Roasting vegetables in a hot oven is a lot easier. It results in nicely browned, tender vegetables with a flavor much like grilled, but sweeter.
You can roast an assortment of brilliantly colored vegetables and serve them in the same dish in which they were roasted, a wide, shallow, ovenproof baking dish or casserole. Or you can roast them on a baking sheet and transfer them to a serving dish.
The various vegetables will all cook in the same amount of time, because they are approximately the same size.
Preheat the oven to 400ºF. Wash all the vegetables and arrange attractively in a shallow, wide ovenproof dish that is pretty enough for the table. Or arrange them in a single layer on a baking sheet with sides. Drizzle all over with olive oil.
Roast on a low shelf in the oven for about 50 minutes to an hour, until the edges of the vegetables are somewhat browned. Remove the baking dish or tray and allow the vegetables to cool.
If you used a baking sheet, transfer the vegetables to a serving platter. To arrange for serving, cut the onions into quarters. Rub off the skins of the peppers with your fingers, and cut the flesh into large segments. Slice the zucchini, squash, tomatoes, and carrots into chunks or strips. Leave the asparagus and garlic head whole.
Be sure to save all the accumulated juices and spoon them back over the vegetables.
Drizzle the vegetables with extra-virgin olive oil and sprinkle with coarse salt. Garnish with the herbs. Serve at room temperature or warm, with toast made from a hearty bread. Butter the bread with the soft, roasted garlic cloves.