To make the meatballs: combine all ingredients in a large bowl. Roll into 1 inch balls, and set aside.
Heat oil in a large pot over medium high heat. Sear the meatballs, about 2 minutes per side. Set aside.
If needed, add a little more oil, and turn the heat down to medium. Add the onions, celery, and carrots. Cook until tender, about 5-7 minutes.
Add the garlic and cook an additional minute.
Stir in the chicken stock, Italian seasoning, and add meatballs back in.
Bring to a simmer, and cook for 10 minutes.
Stir in pasta, and cook an additional 10 minutes.
Add the spinach, and cover to let wilt for 5 minutes.
Serve with fresh pepper, parmesan cheese, and crushed red pepper.