Preheat oven to 475°F and line a large baking sheet with parchment paper.
Combine all the meatball ingredients in a large bowl. Roll into 1-inch balls and arrange on the baking sheet with space between each meatball so air can circulate.
Bake meatballs for 20-25 minutes until browned and cooked through.
For the soup, heat the olive oil in a large pot over medium-high heat. Cook the onions, carrots, celery, and garlic for 5-6 minutes until softened.
Add the chicken broth, Italian seasoning, and orzo pasta. Bring to a boil, then reduce to a gentle simmer. Cook for 10-ish minutes until the pasta is cooked through.
Add the meatballs and bring to a simmer.
Stir in the spinach and serve immediately. Enjoy!
Nutrition information is calculated using an ingredient database and should be considered an estimate.