In a large skillet, sauté the onion and garlic until softened.
In a mixing bowl, combine the cooked turkey, sour cream, cream of mushroom soup, chicken broth, sautéed onions and garlic, and cooked egg noodles. Mix well.
Season with salt and pepper to taste.
Transfer the mixture to a baking dish and top with shredded cheddar cheese.
Bake in the preheated oven for 30-40 minutes, until the cheese is melted and bubbly.
Let cool for a few minutes before serving.
Notes:
This casserole is perfect for using up leftover turkey.