Step 1

Heat 1 tablespoon oil in a large pot over medium-high heat. Add onion, carrot, celery and garlic; cook, stirring occasionally, until the onion is translucent, 4 to 5 minutes. Add broth, cover and bring to a boil. Add orzo, oregano and salt; cover and cook, stirring occasionally, until the orzo is just tender, about 9 minutes.

Step 2

Stir in meatballs and spinach; cook until the meatballs are heated through and the spinach is wilted, 2 to 4 minutes. Serve sprinkled with cheese and drizzled with the remaining 3 tablespoons oil.