How to Make It
Heat the oven to 450°. In a large bowl, toss the eggplant, zucchini, and red onion with 2 tablespoons of the oil. Spread in a single layer on one large or two smaller baking sheets, preferably nonstick. Roast, stirring occasionally, until well browned and tender, about 30 minutes.
Meanwhile, place the tomatoes cut-side up in a small baking dish and sprinkle with 1/4 teaspoon of the salt. Roast until soft, about 20 minutes. Transfer to a food processor or blender and puree.
In a large pot of boiling, salted water, cook the ziti until just done, about 12 minutes. Drain the pasta and toss with the tomato puree, the roasted vegetables, the basil, the remaining 2 tablespoons olive oil, the vinegar, the remaining 1 teaspoon salt, and the pepper.
Variation Ziti with Roasted Vegetables and Cheese: Add some crumbled goat cheese or grated Fontina when you toss the ziti. Or, put the finished pasta in an ovenproof baking dish, top with either of these two cheeses, and run it under the broiler until the cheese is golden brown.