Combine all ingredients for the meatballs in a mixing bowl. Use your hands to mash everything together until well-combined (Note: You can also complete this process using a stand mixer fitted with a paddle attachment). Form meatballs that are 1 to 2 inches in diameter and set them on a plate.

Heat the oil in a large stock pot over medium heat. Wait until the oil is very hot before adding the meatballs.

Carefully place meatballs in a single layer in the stock pot. Brown meatballs 1 to 2 minutes, then flip to brown the other side 1 to 2 minutes. (If necessary, do this in batches until all meatballs are browned (but not cooked through). If desired, drain the pot of any excess fat before continuing.

Pour the chicken broth into the pot with the meatballs, along with the carrots, celery, and white rice. Cover, and bring to a full boil, then immediately decrease heat to a simmer. Cook covered 15 minutes, or until meatballs are cooked through and rice is cooked.

Add the spinach, parsley, and green onion and cover. Cook until spinach has wilted, about 1 to 2 minutes.