1. Heat the oven to 425°F. Toss the zucchini with 1 tablespoon of the olive oil and a little salt and pepper on a 13- by 18-inch baking sheet. Roast, stirring every 15 minutes or so, until fully tender and golden brown, about 30 minutes.
2. Meanwhile, put the remaining ? cup olive oil in a large pot over medium-high heat. When it's hot, add the onion and garlic and cook, stirring occasionally, until softened, 5 to 7 minutes. Add the eggplant and thyme, season with salt and pepper, and continue to cook, stirring frequently, until the eggplant is partially tender and has reduced considerably in volume, about 10 minutes. Add the bell pepper and continue cooking and stirring for another 10 minutes.
3. Stir in the tomatoes and zucchini, cover the pot, and reduce the heat to medium. Cook, stirring occasionally, until the tomatoes have broken down and the mixture is thick. Stir in the basil and olives, then taste and adjust the seasoning. Serve hot, warm, or at room temperature. (Store leftover ratatouille in an airtight container in the refrigerator for up to a week.)
Yield: 4 to 6 servings
Time: About 1 hour