In a large soup pot, heat 2 tablespoons of olive oil over medium heat. Add 1 small diced yellow onion and sauté for about 3-4 minutes until it turns translucent, releasing a sweet aroma. Stir in 2 minced garlic cloves and cook for another 30 seconds until fragrant, ensuring the garlic doesn't burn.

Pour in 4 cups of chicken broth, followed by 1 cup of heavy cream and 1 can of drained diced tomatoes. Stir the ingredients together and bring the mixture to a gentle boil over medium-high heat, watching for bubbles to form.

Once boiling, add 3/4 cup of small pasta and 1 teaspoon of Italian seasoning to the pot. Season with salt and pepper to enhance the flavors. Allow the soup to simmer uncovered for about 10 minutes, stirring occasionally.

Reduce the heat to low and gently stir in 1 pound of fully cooked meatballs and 2 cups of chopped fresh spinach. Simmer the soup for an additional 5-7 minutes until the spinach wilts and the meatballs are heated through.

Remove the pot from heat and stir in 1/2 cup of grated Parmesan cheese until melted and well combined. Adjust salt and pepper if needed.

Ladle the warm soup into bowls and garnish with fresh parsley. Serve hot, accompanied by crusty bread.