The contrast of silky grilled zucchini, creamy ricotta and crunchy nuts provides this dish with satisfying textural complexity. We incorporate lemon two ways, stirring the zest into the ricotta and grilling the halved fruit to bring out a gentler acidity in the juice. Be sure to use a high-quality full-fat ricotta cheese to ensure a creamy texture; low-fat versions can be watery and granular. Also, look for slightly larger zucchini and slice on a sharp diagonal—the larger slices are easier to manage on the grill. Serve with thick slices of grilled bread and a drizzle of syrupy aged balsamic.