Step 1
In a colander set over a large bowl, toss eggplant with 1 teaspoon salt. Let sit at least 30 minutes, then squeeze off excess moisture and pat dry with paper towels.
Step 2
Meanwhile, in a large pot over medium heat, heat 1 tablespoon oil. Add onion and 2 chopped garlic cloves; season with 1/4 teaspoon salt and 1/4 teaspoon pepper. Cook, stirring occasionally, until onions turn translucent, 5 to 6 minutes. Add bell pepper and cook, stirring occasionally, until softened, about 6 minutes. Transfer onion mixture to a large bowl.
Step 3
In same pot over medium heat, heat 1 tablespoon oil. Add zucchini, rosemary, and 2 chopped garlic cloves; season with 1/4 teaspoon salt and 1/4 teaspoon pepper. Cook, stirring often, until zucchini softens and turns golden, about 8 minutes. Transfer zucchini mixture to bowl with onion mixture.
Step 4
In same pot over medium heat, heat 1 tablespoon oil. Add eggplant, thyme, and 2 chopped garlic cloves. Cook, stirring often, until eggplant turns golden and translucent, about 8 minutes. Transfer eggplant mixture to bowl with onion mixture.
Step 5
In same pot over medium heat, heat remaining 1 tablespoon oil. Add chopped tomatoes, granulated sugar, all remaining garlic, 1/4 teaspoon salt, and 1/4 teaspoon pepper. Cook, stirring often, until tomatoes begin to break down and caramelize, 6 to 8 minutes.
Step 6
Add crushed tomatoes, sliced basil, and all reserved cooked vegetables to pot and bring to a simmer. Reduce heat to medium-low and continue to simmer, stirring occasionally, until vegetable textures begin to melt together, 8 to 10 minutes.
Step 7
Top with more basil. Serve with bread alongside.
