Adjust oven rack to lower-middle position and preheat the oven to 450 degrees F. On a wide rimmed baking sheet, mix 6 tablespoons of olive oil with the chili flakes, and herbes de Provence. Toss the eggplant, zucchini, bell pepper, onions, and garlic in the olive oil mixture until well coated and season with salt and pepper. Arrange the vegetables in a single layer on two baking sheets. Roast until vegetables are softened and just beginning to brown, about 10 minutes. Set aside to cool. Peel the paper off the garlic and discard. Lower the oven to 350 degrees F.
