Preheat the oven to 450 degrees. Toss the eggplant with 1 tablespoon of the olive oil and salt to taste. Place on a baking sheet in the hot oven, and roast uncovered for 20 to 25 minutes, stirring from time to time until the eggplant is lightly browned. Remove from the oven.
While the eggplant is roasting, heat a tablespoon of olive oil over medium high heat in a cast iron dutch oven. Add the onions. Cook, stirring often, until they start to brown, about five minutes. Remove to a bowl.
Add the peppers to the pan and cook, stirring often, until the peppers have softened and browned a bit, 5 to 10 minutes.
Stir in the garlic, thyme, oregano, and cook for another minute. Add the zucchini and the roasted eggplant to the pan. Stir gently.
Add the tomatoes, bay leaf, lemon peel, and salt and pepper to taste. Toss everything together, and place over medium-low heat. When the vegetables begin to sizzle, cover, reduce the heat to low and simmer, stirring often, for 30 to 45 minutes until the vegetables are thoroughly tender. Taste and adjust seasonings.
Serve warm. Stir in fresh basil shortly before serving.