In a large saucepan, heat oil over medium heat. Sauté celery, onion, garlic, parsley, Italian seasoning, red pepper flakes, and salt until onion is translucent, about 5 minutes.
Add chicken broth, tomatoes, and tomato sauce. Simmer on low 15 to 20 minutes.
Add pasta and cook 7-10 minutes until pasta is al dente. Add undrained beans. Mix thoroughly and continue cooking until heated through.
Sprinkle shredded Parmesan cheese and fresh parsely on top if desired and serve.
Pasta e Fagioli can be made in the crockpot, but add additional broth and do not add the pasta until the last 20 minutes of cooking.You can substitute other vegetables, legumes, or pasta if you wish, making this a good recipe to use what you have on hand.