Italian Meatball Soup

Name: Italian Meatball Soup
Prep time: 10 min
Cook time: 30 min
Total time: 40 min
Cuisine: Italian
Ingredients: 1 pound meatballs (see note); 1 tablespoon olive oil; 1/2 medium onion (chopped); 4 cloves garlic (minced); 1 (28 fluid ounce) can crushed tomatoes (I use fire roasted); 4 cups beef broth; 1/2 red bell pepper (chopped small); 1/4 teaspoon Italian seasoning; 1/2 teaspoon crushed red pepper flakes (optional); 1.5 cups uncooked fusilli pasta; 1/4 cup fresh basil (torn/chopped); Salt & pepper (to taste); Parmesan cheese (for serving) (optional, to taste)