Preheat oven to 350°F. Grease 9x11 inch baking pan with non-stick cooking spray.
Mix butter, cream of chicken soup, sour cream, shallot, 2 cups cheddar cheese, salt, and pepper in a large bowl. Stir to combine.
Add hash browns and mix. Spoon the hash brown mixture to the prepared pan and spread evenly. Sprinkle with remaining ½ cup shredded cheddar cheese over the top.
Bake in the preheated oven for 45-60 mins until ready.
Serve hot. Refrigerate leftovers in an airtight container and store in the fridge for up to 5 days.