1 2-pound package frozen hash brown potatoes, unthawed
1 10 3/4-ounce can cream of celery soup, undiluted
3 cups (packed) grated sharp cheddar cheese (about 12 ounces)
1 cup sour cream
1 cup finely chopped onion
1 6-ounce can french fried onions

Preheat oven to 350�F. Combine first 5 ingredients in large bowl.
Transfer to 13x9x2-inch glass baking dish.
Bake until top is slightly golden, about 1 hour 10 minutes.
Sprinkle with onions. Bake until golden brown, about 5 minutes.

Serves 12.