Prepare the Mini Meatballs:
In a medium bowl, combine ground chicken or turkey, breadcrumbs, Parmesan cheese, egg, minced garlic, chopped parsley, salt, and pepper. Mix gently until just combined. Do not overmix.
Roll the mixture into small, bite-sized meatballs (about 1/2 to 3/4 inch in diameter).
Heat 1 tablespoon of olive oil in a large pot or Dutch oven over medium-high heat. Brown the meatballs on all sides. You may need to do this in batches. Remove meatballs from the pot and set aside.

Prepare the Soup:
In the same pot, add the chopped onion, carrots, and celery. Sauté over medium heat until the vegetables are softened, about 5-7 minutes.
Pour in the chicken broth and bring to a simmer, scraping up any browned bits from the bottom of the pot.
Add the tiny pasta and return the browned meatballs to the pot.
Simmer for 10-12 minutes, or until the pasta is cooked and the meatballs are cooked through.
Stir in the fresh spinach and cook for another 1-2 minutes, until wilted.
Season the soup with salt and black pepper to taste.
Serve hot, garnished with fresh chopped parsley.