Heat 2 tablespoons olive oil in a large pot over medium-high heat. Add the onion, carrots, and celery to the pot. Stir and cook them until softened, about five minutes or so. Add the chopped spinach and stir until it wilts.
Add 8 cups chicken broth and bring the soup to a simmer. Cover the pot and simmer the soup while you prepare the meatballs. Keep an eye on the pot and adjust the heat to maintain the simmer, as needed.
Make the meatballs: Mix ¼ cup breadcrumbs, 1 egg, 2 tablespoons milk, and 1 teaspoon each of oregano, onion powder, garlic powder, and lemon zest in a large mixing bowl. Add ½ teaspoon each of salt and pepper plus ¼ cup of parsley and stir to combine. Add the ground chicken and mix until just combined.
Scoop 1 tablespoon of the mixture to form each meatball and set them aside on a large plate or sheet pan.
Take the lid off the pot and add the pasta. Simmer the pasta in the soup for five minutes. Drop the meatballs into the soup and simmer them for three to five minutes or until the pasta is tender and the meatballs are cooked through.
Stir in the lemon juice and ¼ cup of parsley before serving.
Notes
You may need adjust the salt depending on the chicken broth you use. Give the soup a taste at the end and add more if you think it needs it.A tablespoon cookie scoop makes it easy to scoop and form the meatballs. If you can't find mini bow tie pasta, you can use a similar short pasta shape that cooks in the same amount of time like mini penne, rotini, small shells, or fusilli. You can also use dried egg noodles.If you have leftover soup, store it in an airtight container in the refrigerator. The pasta will absorb some of the broth while it sits, so you may want extra broth on hand to add when you warm it up.