In a bowl, mix together the chopped onion, half of the shredded cheddar cheese, milk, cream of chicken soup, and sour cream.
Stir in the hash browns until coated.
Pour into the pan and top with remaining shredded cheddar cheese.
Cover with foil and bake for 45–50 minutes.
Remove foil and bake an additional 5–10 minutes until cheese is lightly browned.
Video
Notes
This casserole can be assembled before hand, covered and store in the refrigerator for 3-4 days. Then bake according to the recipe. *Leftovers can be stored in the refrigerator for up to 5-7 days.