How to Make It
Heat the broiler. In a small bowl, whisk together 1 tablespoon of the oil with the vinegar, 1 teaspoon of the salt, and a few grinds of pepper and brush the mixture on the cut sides of the zucchini, eggplants, and onion. Arrange them cut-side up on a large, shallow baking pan. Broil the vegetables until golden brown and tender, 8 to 10 minutes per side. Transfer to a cutting board. Cut the zucchini crosswise into thin slices. Cut the eggplant into 1-inch pieces. Chop the onion coarsely.
Heat the oven to 350º F. Meanwhile, in a large pot, cook the pasta according to the package directions; drain. Return the pasta pot to the stove, add the garlic and the remaining tablespoon of oil, and cook over low heat until the garlic sizzles. Stir in the oregano and mint.
Add the cooked pasta, broiled vegetables, chopped tomatoes, Feta, the tomato sauce, pepper flakes, remaining 1/2 teaspoon salt, and a few more grinds of pepper. Transfer to a 13-by-9-inch baking dish. Sprinkle the top with the mozzarella.
Bake, covered, for 30 minutes. Uncover and bake for 15 to 20 minutes more or until the cheese is melted and golden, and a knife inserted in the center for 5 seconds comes out hot.