Preheat the oven to 350 degrees.
Melt the butter in a pot over medium heat.
Stir in the onions, and saute for 3 minutes.
Mix in the mushrooms, and continue to saute until the vegetables have softened.
Add the garlic and poultry seasoning, and saute for 30 seconds longer.
Pour in the chicken broth and heavy whipping cream.
Sprinkle lightly with a bit of xanthan gum, and simmer until the sauce has thickened.
Add in the sour cream and parmesan cheese.
Season with salt and pepper to taste, and add more xanthan gum if the mixture is not thickened enough.
Combine the bread, turkey meat and green beans in a large mixing bowl.
Pour the soup mixture into the mixing bowl, and stir to combine well.
Spread the mixture into a well greased 9x13 baking dish.
Stir together the pork rind crumbs and remaining parmesan cheese. Sprinkle the mixture over the casserole.
Bake for 20-25 minutes.