In a microwave-safe bowl, add onions, carrots, and celery. Cook for 3 minutes to soften.
Add to crockpot, cooked onions, carrots, celery, garlic, broth, pasta sauce, beans, drained tomatoes, bay leaves, Italian seasonings, and pepper. Mix well. Drop-in Parmesan cheese rind. Cover and cook on LOW heat a total of 6 to 7 hours or cook on HIGH heat for a total of 3-3½ hours. Time varies depending on your crock-pot. Mine cooked on high heat for 3 hours.
Note: One hour before the soup is done, add zucchini. Cover and cook on high heat for the last hour. Or, cooked chopped zucchini in microwave for 2-3 minutes and add to soup with cooked pasta and spinach and continue to cook 10 minutes. Remove bay leaves and parmesan rind. Adjust seasonings, if desired.
To serve: Add 2 cups of soup to each bowl and top with grated parmesan cheese, if desired.
This soup freezes great!