In a bowl, combine diced tomatoes, tomato paste, Italian seasoning, black pepper and bay leaves.
Pour half the tomato mixture into the slow cooker.
Add the eggplant, zucchini, yellow squash, onion, red bell pepper and garlic to the slow cooker. Top with the remaining tomato mixture.
Cook on LOW for 7-8 hours or HIGH for 3-4 hours.
Garnish with chopped basil and parmesan cheese.
