Just like a steak or chop, vegetables become beautifully caramelized when cooked on the grill. The grill’s hot fire brings out the natural sugars in the vegetables, so they actually retain more of their flavor, vitamins and minerals than they do when cooked in water. Asparagus, corn, squash and peppers — summer vegetables are right at home over a bed of hot coals.
Choosing: In-season vegetables grown close to home are best — they should also be plump, moist and unwrinkled. Follow the guidelines outlined below for each ingredient.
Preparing: To prevent vegetables from sticking to the grill rack, coat both the rack and the vegetables with oil before grilling. A grilling basket is handy for cooking small vegetables that may fall through the spaces in the rack.
Testing for Doneness: Piercing a vegetable with a skewer or the tip of a knife will give you some idea of whether or not it’s done. However, the best way to test a vegetable for doneness it to cut off a piece and eat it. Some vegetables, such as asparagus and fennel, are most satisfying when tender-crisp, which means tender when you first bite into them and crunchy at the center. Other vegetables, such as eggplants and mushrooms, should be cooked until soft throughout.
Medium-sized and fat stalks grill better than very thin spears, which can be bitter. Peeling the bottom third of the spears with a vegetable peeler will help them cook evenly.
Recipe: Asparagus with Saffron Aioli
Select heads of Belgian endive and radicchio that are firm, fat and crisp, with tight, unblemished leaves.
Recipe: Grilled Artichokes and Radicchio with Gremolata
Look for firm ears with plump kernels and a lot of creamy colored silk; avoid ears with heavily soiled or slimy fringe. The husks should be bright green and appear moist, not dried out.
Recipe: Corn with Sorghum Butter
Look for evenly colored eggplants with shiny skin. Cut globe eggplants into slices for the grill; cook Asian eggplants whole or halved.
Recipe: Eggplant, Zucchini and Squash Kabobs
Choose fresh bulbs that are smooth and tightly layered with no cracks or bruises. White and pale green, rounded bulbs tend to be more succulent than yellow or thin ones.
Recipe: Fennel with Romesco Sauce
Look for mushrooms with relatively clean, firm caps. For portobellos, choose those that are evenly sized and have gills that appear clean, dry and distinct.
Recipe: Portobello Burgers
Look for onions that are firm with smooth, dry skins. Avoid any with soft spots, particularly at the stem end; green shoots; moldy areas; or moist, wrinkled skins. In the spring, seek out sweet onions such as Maui, Vidalia or Walla Walla.
Recipe: Grill-Roasted Pork Loin with Onions
Look for peppers and chilies with smooth skin — they will be easier to char on the grill than gnarled or grooved peppers. Thin-skinned varieties need a gentler touch so that they don’t develop holes while grilling from too-high heat.
Recipe: Grilled Vegetable Platter with Picnic Vinaigrette
Look for firm, unblemished tubers that are not wrinkled, tinged with green or cracked. Avoid potatoes that have sprouted buds.
Recipe: Grilled Fingerling Potatoes
Select zucchini, yellow crooknecks, pattypans and other summer squashes that are mature enough to have full flavor yet small enough to be tender, without large seeds.
Recipe: Grilled Summer Squash with Fresh Mint Vinaigrette
Select tomatoes only in season, and make sure they are firm but ripe. Heirloom varieties are particularly flavorful. Never store tomatoes in the refrigerator or they will become mealy; a sunny windowsill is a good place to store underripe tomatoes.
Recipe: Grilled Fennel and Tomatoes on the Vine