In a large Dutch oven, with a lid, over medium heat, add the oil. When the oil is hot, add the onions. Season with salt and pepper. Sauté until soft, about 6 minutes. Add the garlic and eggplant. Season with salt and pepper. Sauté until wilted, about 4 to 6 minutes. Add the zucchini, tomatoes, and peppers. Season with salt and pepper. Bring to a simmer and cook until the liquid as evaporated and the vegetables are very soft, about 30 minutes. Taste and season if necessary. Serve with the salt cod.
Yield: about 6 cups