Melt the Butter: Melt 1 cup of butter in a microwave-safe bowl or small saucepan over low heat. Set aside.
Prepare the Potato Mixture: Add the Southern-style hash browns, sour cream, and cream of chicken soup to a large mixing bowl.
Add the Cheddar Cheese and Onion: Stir in the shredded sharp cheddar cheese and finely diced yellow onion.
Add the Melted Butter and Seasoning: Pour the melted butter into the bowl and season with salt and black pepper to taste.
Mix Everything Together: Stir all the ingredients until the potatoes are evenly coated and everything is well combined.
Preheat the Oven and Prepare the Dish: Preheat the oven to 180°C (350°F). Lightly grease a 2.8-litre casserole dish with cooking oil.
Transfer the Potato Mixture: Spread the potato mixture evenly into the prepared casserole dish.
Crush the Crackers: Place about 15 crackers in a resealable food bag and crush them with a rolling pin until you have small crumbs.
Melt the Topping Butter: Melt 1½ tablespoons of butter in a small microwave-safe bowl.
Add the Cracker Topping: Sprinkle the crushed crackers evenly over the potato mixture.
Drizzle with Melted Butter: Pour the melted butter over the cracker crumbs, spreading it evenly across the topping.
Bake the Cheesy Potatoes: Bake uncovered for 60 minutes, or until the edges are bubbling and the topping is golden.
Rest and Serve: Remove the casserole from the oven and let it rest for a few minutes before serving warm.