Grilled lettuce is a method of preparing a head of lettuce so it remains crisp when eaten but also concentrates the delicate flavor so it is more prominent when included in a dish. When grilled, lettuce takes on a roasted flavor and can be served as a vegetable all by itself, included in a salad as other roasted vegetables might be, or coated in a sauce or other ingredients and presented as a main dish. Most often, the lettuce is marinated before being grilled, or it can be brushed with olive oil and other spices to help accelerate the browning process once over the heat. While on the grill, grilled lettuce needs to have nearly constant attention, because the water contained in the leaves can easily turn completely to steam, potentially turning the head of lettuce into a crisp, charred and unpleasant-tasting mass.
Nearly any type of lettuce can be made into grilled lettuce, with enough care. The most popular type, however, is romaine lettuce that has been cut in half lengthwise, because it holds together well and can be easily turned. Belgian endive, radicchio and escarole also are good choices, because they can withstand the heat of the grill and maintain their shape. In all cases, the lettuce should be cut into halves or quarters that are manageable but intact enough to hold together as they cook and are handled.
To prepare the cut lettuce for the grill, the most basic method is to coat the outside of the lettuce with oil, salt and pepper. A method that will yield a more flavorful type of grilled lettuce involves marinating the lettuce. The marinade can include oil, balsamic vinegar, soy sauce or something creamier, such as buttermilk. If the lettuce is placed on the grill without any coating, it can be more difficult to get color on the outside without losing the crispness of the leaves.
There are two main ways to cook grilled lettuce. The first involves a moderately heated grill that is prepared for indirect grilling. In this method, the lettuce is placed on the grill and allowed to cook for a few minutes on each side, during which time the outside will slowly brown in small patches and the inside will steam slightly from the water content of the leaves but still remain crisp.
For smaller pieces of lettuce, direct grilling over high heat can be used. This involves placing the lettuce directly over the heat source and watching very closely as it quickly browns on the outside. The interior will heat through quickly in a small bunch of lettuce, although this method will leave the inside of larger heads almost raw, which can be undesirable if the lettuce was marinated.
Finished grilled lettuce can be served as a vegetable along with other roasted vegetables, or it can be chopped in large pieces and served with barbecued meat. Alternately, grilled lettuce leaves can be peeled away from the core and used as a wrapper for other foods. The roasted taste of the lettuce also can serve as an addition to robust salads such as Caesar salad.