Preheat the oven to 350°F (175°C). Grease a 9x13-inch baking dish and set aside.
In a large mixing bowl, combine the cream of chicken soup, sour cream, cream cheese, and melted butter. Stir until smooth and well combined.
Add the shredded cheddar cheese, garlic powder, onion powder, and a pinch of salt and pepper. Stir to incorporate.
Add the thawed hashbrowns to the mixture and gently fold everything together until well mixed.
Pour the mixture into the prepared baking dish and spread it evenly.
In a small bowl, mix the crushed cornflakes with a tablespoon of melted butter. Sprinkle the cornflake mixture over the top of the casserole.
Bake in the preheated oven for 40-45 minutes or until the top is golden brown and bubbly.
Let the casserole sit for 5-10 minutes before serving.
Enjoy your delicious Funeral Potatoes with Hashbrowns!