This dish is also known as "funeral potatoes" around here because it is frequently served along with ham, jello salad, and rolls at the conclusion of Mormon funerals. It's not healthy, probably hastening the onset of additional funerals, but it is genuine comfort food for many.
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 degrees. Combine first 5 ingredients in large bowl. Transfer to 13 x 9 x 2-inch glass baking dish. Bake until top is slightly golden, about 1 hour 10 minutes. Sprinkle with fried onions. Bake until golden brown, about 5 minutes. Serves 12.