This tastes a lot like the one at Cracker Barrel. You can prepare it the night before, leave it covered in the fridge overnight, and pop it in the oven to bake in the morning. This is my adaptation of this recipe.
2 lbs shredded potatoes (no need to peel if you scrub them clean) *
1 16 oz tub of sour cream
1/4 cup butter, melted *
1 medium onion, diced small (about 1/2 cup) *
1 packet chicken gravy mix
2 cups shredded sharp cheddar cheese *
1 tsp salt
1/4 tsp pepper
Mix all ingredients in a large bowl. Transfer to a 13x9 inch baking pan and bake at 350 degrees for about 40 minutes, or until golden.
* Note: If you have an electric shredder (I like this one), you can use it to shred all these ingredients, which significantly cuts down on prep time. For the butter, simply shred fridge-cold instead of melting it.