In a skillet, melt 2 tablespoons of butter over medium heat. Add the finely chopped yellow onion and sauté until it becomes softened and golden, about 5–7 minutes.

In a large mixing bowl, combine the cream of chicken soup, 2 cups of sour cream, and 2 cups of shredded sharp cheddar cheese. Gently fold in the sautéed onions along with the remaining melted butter, seasoning with 1 teaspoon of salt and ½ teaspoon of black pepper.

Carefully fold in the frozen shredded hashbrowns into the creamy mixture until evenly coated.

Grease a 9x13-inch baking dish and pour the Cheesy Funeral Potatoes mixture into the dish, ensuring an even layer.

In a small bowl, combine the crushed cornflakes with the remaining melted butter then sprinkle this topping evenly over the casserole.

Place your baking dish in a preheated oven at 350°F and bake uncovered for approximately 45 minutes, until golden brown and bubbly.

Once baked, remove from the oven and let it rest for 5–10 minutes before serving.