Heat olive oil in a large skillet over medium high heat. Add in carrots, celery and onion and sauté for 3-4 minutes or until the veggies start to get some color on them.Add the vegetable broth to the pan that the vegetables were cooked in.
Add in the garlic and cook for an additional minute.Transfer the veggies to a slow cooker.Deglaze the pan by scraping the brown bits off of the bottom. This adds so much flavor to the soup.
Transfer the stock to the slow cooker with the vegetables then add the beef stock, tomatoes, parmesan rind, rosemary sprigs, Italian seasonings, bay leaves, Worcestershire sauce and crushed red pepper flakes.
Cook on high for 2-3 hours or on low for 4-6 hours.
Add in zucchini, spinach, pasta, beans and cook on high heat for an additional 30 minutes or until the pasta is tender.
Season soup to taste with salt, pepper and crushed red pepper flakes if desired.Serve immediately with parmesan cheese for serving!
Notes
Original recipe from chefsavvy.com. Please do not publish my recipe or pictures without linking back to the original post. Thank you!