In a medium bowl, combine ground turkey, panko breadcrumbs, egg, minced garlic, Italian seasoning, salt, and pepper. Mix gently until just combined. Roll into 1-inch meatballs.
Heat olive oil in a large pot or Dutch oven over medium heat. Add chopped onion, carrots, and celery. Cook until softened, about 5-7 minutes.
Add minced garlic to the pot and cook for 1 minute more until fragrant.
Pour in the chicken broth and bring to a simmer.
Carefully add the turkey meatballs to the simmering broth. Cook for 8-10 minutes, or until cooked through and no longer pink inside.
Stir in the cooked quinoa and cannellini beans. Cook for another 2-3 minutes to heat through.
Add the fresh spinach and stir until wilted, about 1-2 minutes.
Season the soup with salt and pepper to taste.
Ladle soup into bowls and serve hot.
Notes
This soup can be made ahead of time and reheated. For best results, add spinach just before serving.