1. Cut first 5 ingredients into 1-inch pieces.
2. Sauté onion and garlic in hot oil in a large skillet over medium heat 5 to 7 minutes or just until onion is tender. Stir in tomatoes and next 2 ingredients, and sauté 8 to 10 minutes or just until eggplant begins to soften. Stir in bell peppers, zucchini, and squash; cover and cook, stirring occasionally, 8 to 10 minutes or until vegetables are tender and liquid is slightly reduced. Stir in basil. Add salt and freshly ground pepper to taste, and sauté 3 minutes.