Combine the chopped onion, beef, turkey, bread crumbs, salt, Italian seasoning, red pepper flakes, garlic and Parmesan cheese. Using your hands mix well.
Shape the mixture into one inch balls.
Bring a large pot of water to a boil for your noodles.
Add your oil to a skillet and heat it over medium heat. Brown the meatballs in the skillet.
Once your meatballs are cooked you will deglaze the pan with your beef broth.
Stir in your salt, pepper and Italian seasoning.
Let your meatballs simmer for 10 minutes.
Meanwhile cook your noddles as per the direction on the packaging.
Create a slurry with the milk and cornstarch. Add the mixture to the meatballs and bring it to a boil to thicken.