1/4 cup diced yellow onion
1 tbsp butter, cut into thin pats
1 cup grated cheese (cheddar or your favorite blend)
1 can (10 3/4-oz) cream of celery soup, undiluted
1/2 cup milk
In a casserole dish layer the potatoes, onion, cheese and butter.
Pour the soup into a small mixing bowl and whisk in the milk until smooth; pour over the ingredients in casserole dish. Cover and bake at 350 degrees for 1 hour. Uncover and bake another 15 minutes for the top to brown.