In a large (6-quart) crockpot, add the diced onion, diced carrots, chopped celery, tomato sauce, minced garlic, BUSH'S® Cannellini Beans, BUSH'S® Organic Dark Red Kidney Beans, and undrained fire-roasted tomatoes.
Add the sugar, seasonings and salt + pepper to taste (I usually don't add salt until the very end since the stock has a good amount of salt; I add in about 1/2 teaspoon freshly cracked pepper). Add in bay leaves.
Add 4 cups of the vegetable stock. If you want a brothy (and less chunky) soup, use 6 cups of vegetable stock. Stir everything together and cover. Cook on low for 5-7 hours or high for 2.5-4 hours (until vegetables are tender and flavors are sufficiently melded).
About 40 minutes before the soup is fully cooked add in the chopped zucchini. Cover and cook for the remaining 40 minutes.
Cook the pasta (following package directions) on the stovetop until al dente. Alternatively, you can add the uncooked pasta to the crockpot at the same time you add the zucchini. (I prefer the pasta to be cooked separately to make sure it's evenly cooked and doesn't get bloated). If you decide to cook the pasta in the crockpot, add an additional two cups of vegetable stock.
Just before serving, stir the spinach into the crockpot and allow it to wilt (3-4 minutes). Ladle the soup into bowls and add a large spoonful of the cooked pasta to individual bowls (stir it in). Add a generous handful of parmesan cheese and serve with crusty bread.
Total time doesn't include the crockpot cook time.