Aunt Audrey's Hashbrown Casserole

I have gotten RAVE reviews on this casserole and everyone always wants me to bring it to the next cookout. Ben's Aunt gave this recipe to me at my bridal shower :)

2 lb bag frozen has browns, thawed
1 pint sour cream (this is 16 ounces but I only use 8 because I'm not a fan of sour cream)
2 cups grated cheddar cheese
1 1/2 cups onion, chopped
2 sticks butter
1 can cream of chicken soup
2 cups crushed Ritz crackers

Melt 1 stick butter, place in 9 x 13 casserole dish with hashbrowns, sour cream, cheese, onion and cream of chicken soup. Mix until through combined. Melt other stick of butter and mix in crushed Ritz crackers until combined. Pour cracker mixture over casserole. Bake at 375 degrees for 45 minutes.