When it's too hot to cook indoors, turn on your barbecue and grill some of summer's best bounty. Although there's a bit of prep work involved, your efforts will be rewarded with a beautiful array of colorful, healthy vegetables that taste great hot or cold. Use your imagination and experiment with different herbs and flavored olive oils. These suggestions are just a starting point! Cooking times are only rough estimates: you'll be the best judge of your barbecue and its idiosyncrasies.
Remove and discard the stems from the mushrooms. Mix the olive oil with the balsamic vinegar. Liberally brush the mushroom caps on both sides and set aside.
Slice the eggplant lengthwise into 3/8-inch-thick slices and rub both sides with a garlic clove. Brush with remaining oil and vinegar mixture. Set aside.
Slice the zucchini and summer squash lengthwise into 3/8-inch thick slices. Rub the cut surfaces with the garlic clove, then brush with basil oil. Season with salt, pepper, and the herb of your choice. Set aside.
Peel the asparagus stalks and liberally brush with the lime- or lemon-flavored olive oil. Season with salt and pepper, and set aside.
Heat your barbecue to its highest setting and adjust the grill so it's closest to the flame. You want a hot fire to cook these vegetables. Begin with the peppers, as these take the longest. Blacken and char the skin on the peppers as completely as possible. Keep turning the peppers, and when they're suitably charred, place them in a paper bag, seal tightly, and let it sit for 8 to 10 minutes. Then remove them from the bag and peel off the skins. Cut the peppers into 1-inch-wide strips, and discard ribs and seeds.
Next cook the eggplant, about 3 minutes per side if your grill is set close to a high heat. Once you've flipped the eggplant, brush the grilled surface with the pesto.
The zucchini and summer squash should cook in the same amount of time if the slices are of uniform thickness. Generally, these need to be turned several times to ensure even cooking. The vegetables should be tender but not mushy, about 5 to 10 minutes total cooking time.
The asparagus cooks very quickly, about 2 or 3 minutes if you like it al dente. Make sure you place the spears horizontally on your grill so they don't fall through! Turn frequently with tongs.
Grill the mushrooms last. Begin cooking with the gill side down, about 2 minutes. Turn, brush with the oil and vinegar mixture, and grill another minute or two to cook through. Be careful not to let the mushrooms dry out.
Arrange your assortment of vegetables decoratively on a large platter. Serve immediately or let them cool to room temperature. Leftovers can be refrigerated and eaten the next day; they will warm nicely in the microwave if you prefer them hot.