Preheat oven to 350° Fahrenheit.
Place large cast-iron skillet on stovetop over medium heat. When skillet is warm, add 2 tablespoons ghee. Let ghee melt completely, swirling and tilting skillet as needed to distribute oil across skillet.
When ghee has melted, add 3 cups diced white onion, 2 cups diced celery, 1 cup diced mushrooms, 1 cup diced apples, ¼ cup dried cranberries, ¼ cup chopped flat-leaf parsley, 4 teaspoons poultry seasoning, ½ teaspoon salt, and ½ teaspoon freshly cracked black pepper to skillet. Stir to incorporate.
Sauté ingredients until onion, celery, mushrooms, apples, and cranberries are very soft, approximately 6 to 10 minutes, stirring occasionally.
Once ingredients have softened, remove skillet from heat. Add 2 cups super-fine blanched almond flour to skillet and stir until ingredients are well incorporated.
Crack 3 large eggs into small bowl and whisk well until eggs are fully combined and mixture is no longer streaky.
Add whisked eggs to skillet and stir until all ingredients are fully incorporated.
Optional: If not using cast-iron or other oven-safe skillet, lightly grease 9x9 baking dish with avocado oil, refined coconut oil, or ghee. Transfer mixture to lightly-greased 9x9 baking dish and spread mixture out evenly across baking dish.
Once ingredients are fully incorporated, spread mixture evenly across skillet. Place cast-iron skillet (or baking dish) in preheated oven. Bake stuffing 45 minutes.
After 45 minutes, check doneness of stuffing. Continue baking stuffing as needed, checking doneness often, until stuffing is baked-through and browned on top.
When stuffing is fully baked, carefully remove skillet (or baking dish) from oven. Set stuffing aside to rest 5 minutes, then serve warm.