There's plenty of room for experimentation here. We've used grilled eggplant, zucchini, bell peppers, and onion sandwiched in crusty rolls with a little pesto. Fennel, endive, or mushrooms would make fine vegetable substitutes; sun-dried tomatoes or white-bean puree can replace the pesto; or omit the condiment altogether and top the sandwich with whole fresh basil or mint leaves. You can even change the cooking equipment, using the broiler or a grill pan in lieu of an outdoor grill. More Sandwich Recipes
How to Make It
Light the grill. In a large bowl, combine the oregano, the basil, if using, the salt, black pepper, vinegar, and oil. Add the eggplant, zucchini, bell peppers, and onion and stir to coat. Grill the vegetables in batches, turning once, until lightly browned and tender, 10 to 15 minutes per batch.
Spread the inside of each roll with 1 tablespoon of the pesto. Sandwich the grilled vegetables, lettuce, and tomatoes in the rolls.
Notes
Slice zucchini lengthwise for grilling, so that you won't have to contend with all those little rounds of squash threatening to fall through the grate.