Heat olive oil in a large stockpot over medium heat.
Add onion, carrots, and celery; sauté for 6 minutes until vegetables begin to soften.
Add minced garlic and cook for 1 minute until fragrant.
Pour in the beef broth and Italian seasoning; increase heat to high and bring to a boil.
Add the dried orzo and cook for 8 minutes, or until just al dente.
Reduce heat to medium-low and stir in the cooked meatballs and heavy cream.
Simmer for 5 minutes until the meatballs are heated through.
Add the baby spinach and parmesan cheese, stirring until the spinach is wilted and cheese is melted.
Season with salt and black pepper to taste and serve immediately.