In a large pot, heat 1 tablespoon of the olive oil over medium heat. Add the onions and cook until softened, about 5 minutes.

Add 2 more tablespoons of olive oil to the pan and add the eggplant. Sauté for about 5 minutes until the eggplant has softened.

Add the remaining 1 tablespoon of olive oil to the pan and add the peppers and squash. Sauté for 2-3 minutes until slightly softened, then add the garlic and cook for 30 seconds more.

Add the diced tomatoes, tomato paste, bay leaf, thyme and rosemary, and season with salt and pepper to taste. Bring to a boil, then reduce heat to medium low and simmer for 20-30 minutes or until the vegetables are the desired level of doneness. Cover the the pot for the first 10 minutes to allow the vegetables to steam, then remove the lid for the remaining cooking time to allow the liquid to evaporate.

Remove from heat and stir in the capers, chopped basil and adjust the seasoning if necessary. Enjoy!