1. To me, you really need the mirepoix - the onions, carrots, and celery - but all other vegetables are optional. Leave them out or substitute/add others such as corn, peas, cabbage, yellow wax beans, lima beans, or even squash, turnips, parsnips, or sweet potatoes. You can also add more kinds of beans - buy a can or bag of those mixed beans and add it instead of the kidney beans
2. Cook the onion, carrots, and celery in the oil over medium heat until they have started to soften. Use a large soup pot for this and this will be a one-pot meal!
3. Season this mixture with salt and pepper and stir in the garlic. Turn down the heat. Add the remaining ingredients, except for the pasta (and parsley and Parmesan if using). Simmer, covered, for 45 minutes.
4. Add the pasta and continue to cook for an additional 10-15 minutes, uncovered until pasta is cooked through.
5. Taste and add more salt and pepper and Italian seasoning if needed. Don’t forget to remove the bay leaves. Serve topped with parsley and Parmesan if desired.

To make in a slow cooker:

1. Eliminate the olive oil, unless you want to cook the mirepoix (onions, carrots, and celery) on the stovetop and then add to the slow cooker. This is not necessary, but some people prefer it.
2. Combine all ingredients except the pasta, spinach, and zucchini in the slow cooker.
3. Cook for 6-8 hours on low or 3-4 hours on high.
4. Half an hour before you are ready to serve the soup, add the pasta, spinach, and zucchini. Cook for another 30 minutes. Remember to remove the bay leaves. Serve garnished with parsley and Parmesan if desired.