Step 1: In a large bowl, combine ground beef, ground pork, breadcrumbs, Parmesan cheese, egg, 2 cloves minced garlic, 2 tablespoons chopped fresh parsley, 1 tablespoon chopped fresh basil, 1/2 teaspoon salt, and 1/4 teaspoon black pepper. Mix gently until just combined, being careful not to overmix.
Step 2: Roll the mixture into 1-inch meatballs. You should get about 35-40 meatballs. Place them on a baking sheet.
Step 3: Heat 1 tablespoon olive oil in a large Dutch oven or soup pot over medium-high heat. Working in batches, brown the meatballs on all sides until lightly golden. Remove browned meatballs and set aside.
Step 4: In the same pot, add the remaining 1 tablespoon olive oil if needed. Add chopped onion, carrots, and celery. Sauté for 5-7 minutes until the vegetables begin to soften. Season with 1/2 teaspoon salt and 1/4 teaspoon black pepper.
Step 5: Stir in the remaining 3 cloves minced garlic and dried Italian seasoning. Cook for 1 minute until fragrant.
Step 6: Pour in beef or chicken broth, crushed tomatoes, and add the bay leaf. Bring the mixture to a simmer.
Step 7: Gently add the browned meatballs back into the simmering broth. Add the small pasta. Reduce heat to low, cover, and simmer for 15-20 minutes, or until the pasta is al dente and the meatballs are cooked through.
Step 8: Stir in the fresh spinach. Cook for another 2-3 minutes until the spinach is wilted. Add the remaining 1/4 cup chopped fresh parsley and 1/4 cup chopped fresh basil.
Step 9: Taste and adjust seasoning as needed. Remove the bay leaf before serving.
Step 10: Serve hot, garnished with extra fresh herbs and grated Parmesan cheese, if desired.