Heat olive oil in a large heavy pot over medium high heat.

Add the diced onion and cook until it just begins to soften, about 2 minutes.

Add celery and carrots; cook, stirring frequently, for another 3 minutes.

Add garlic and cook just until fragrant, about 30 seconds.

Add the sausage to the pot, crumbling as it cooks.

Cook until the sausage is no longer pink.

Stir in Italian seasoning and red pepper.

Stir in tomatoes and stock.

Bring the mixture to a boil. Reduce heat and simmer 30 minutes.

Stir in the beans and ditalini. (Add an extra cup of stock or water at this point if it's boiled down too much.)

Simmer for 6- 8 minutes or until pasta is tender.

Serve hot with Parmesan cheese and some chopped green onions