Grilled Summer Vegetable Sandwich with Romesco Sauce and Serrano Ham

Save this pressed sandwich for the height of summer, when you can get locally grown zucchini, eggplant, and tomatoes. After grilling the zucchini and eggplant, layer them on a roll slathered with romesco, the Spanish tomato and almond sauce. (Refrigerate any unused romesco and use it within a day or two on another sandwich or with grilled fish or shrimp.) The sandwich can be made hours ahead, so it’s a good choice for a backpack lunch or a picnic. Omit the ham to make it vegetarian. Piquillo peppers are small, slightly spicy roasted red peppers sold in jars at shops that specialize in Spanish or Mediterranean foods (see Ingredient Resources, page 193).