In a large soup pot, melt the butter over medium heat. Add the diced onion, carrots, and celery, and cook until softened, about 5-7 minutes.
Add the garlic and Italian seasoning and stir to combine, cooking for 1 more minute.
Add the broth and turkey and bring to a simmer. Cook for 10 minutes.
In a small bowl or mason jar, add the milk and flour. Whisk or shake to combine.
Add the milk/flour mixture to the pot and let it cook for 5 minutes to thicken slightly.
Add the gnocchi and cook another 5-6 minutes, until the gnocchi is cooked and the soup has thickened even more.
Add the Parmesan cheese and stir to combine and melt.
Serve and enjoy!