How to Make It
Light the grill or heat the broiler. In a large shallow bowl, toss the eggplant, zucchini, bell pepper, and garlic with 2 tablespoons of the oil, 1/4 teaspoon of the salt, and 1/8 teaspoon of the black pepper. If using the broiler, arrange the vegetables in a single layer on one large or two smaller baking sheets, preferably nonstick. Grill or broil in batches, turning the vegetables once, until they are tender and lightly browned, 10 to 12 minutes. Cut the vegetables into 1 1/2-inch pieces.
In a small glass or stainless-steel bowl, whisk together the remaining 4 tablespoons olive oil, the lemon zest, lemon juice, parsley, cumin, and the remaining 1/2 teaspoon salt and 1/8 teaspoon pepper.
In a large pot of boiling, salted water, cook the penne rigate until just done, about 13 minutes. Reserve about 3 tablespoons of the pasta water. Drain the penne and toss with 1 tablespoon of the reserved pasta water, the oil-and-lemon-juice mixture, and the vegetables. Add more pasta water if the pasta seems dry. Top with some Parmesan cheese and pass additional Parmesan at the table.