Crock-Pot Cheesy Hash Brown Casserole

* 32 ounces frozen hash browns, thawed, not shredded

* 1/2 cup butter, melted

* 1 medium onion, chopped

* 1 can Cream of Chicken Soup

* 8 ounces sour cream

* 1 teaspoon Cajun seasoning

* 1/2 teaspoon granulated garlic

* 1/2 teaspoon black pepper

* 2 cups sharp shredded cheddar cheese, 1 cup to mix with hash browns and 1 cup for topping