Preheat oven to 450°F. Spray a 9x5-inch loaf pan with cooking spray.
Stir together Pork Rind Crumbs, shredded cheese, 3 eggs, sour cream, baking powder, and garlic powder.
Pour mixture into a greased loaf pan and bake for 25 minutes. Remove from baking pan and cool completely.
Turn the oven down to 375°F. Butter a baking dish.
Melt 4 tablespoons butter in a large pan and stir in onion, celery, mushrooms and parsley. Cook until ingredients are soft, stirring frequently.
Once cooled, cut your Pork Rind Bread into small, 1-inch cubes and place them in a large mixing bowl. In another bowl, beat the remaining egg with a fork or whisk and pour it over the top of your bread cubes, followed by your onion mixture, the remaining spices, and the chicken stock.
Stir all ingredients together, transfer to a baking dish, and bake at 375 degrees for 25-30 minutes.