I got this recipe from a local restaurant I worked at in HS. It's very similar to Cracker Barrels Hashbrown Casserole.
1 bag frozen shredded potato hashbrowns (or you can shred your own potatoes, obviously)
1 cup sour cream
1 can cream of chicken soup (though I've substituted cream of mushroom & cream of broccoli w/much success)
2 cups shredded cheddar cheese
salt & pepper to taste
1/2 onion, finely chopped
Rice Krispies cereal
4 tbsp. butter
Mix potatoes w/sour cream, soup, cheese, onion, salt & pepper.
Spread evenly in a greased 13x9" pan.
Top w/crushed Rice Krispies & several pats of butter.
Bake at 350F for 30-45 minutes or until top is beginning to brown & crisp.
you can easily make this ahead of time & refrigerate, just allow more time in the oven.