Step 1

If your slow cooker has a brown or sauté function: Heat the olive oil in the slow cooker and add the onion, celery, garlic, oregano, and sage. Cook until the onion and celery are soft and translucent, then switch the slow cooker function to high heat and add all remaining ingredients except the pasta, Parmesan cheese, and minced parsley.

Step 2

If your slow cooker does not have a brown or sauté function: Add all ingredients to the slow cooker except the pasta, Parmesan cheese, and minced parsley.

Step 3

Stir together, then cover and cook on high for 3 1/2 hours or low for 7 hours.

Step 4

Open the slow cooker and stir in the pasta, then cook for about 20 minutes more until the pasta is tender.

Step 5

Ladle the soup into bowls and sprinkle Parmesan and parsley over each bowl. Serve immediately.

Step 6

Make Ahead: If you are letting the soup cook overnight or if the slow cooker will finish its cooking cycle while you're out of the house, you can boil the pasta separately. Drain the cooked pasta, toss with 1 teaspoon olive oil or vegetable oil to prevent sticking, and refrigerate until ready to serve. Add the cooked pasta to the soup just before serving.