Grandma Beth's Cheesy potatoes

Grandma Beth's Cheesy potatoes

1/2 cup onion, grated
6 medium potatoes
3/4 cup butter
3/4 cup flour
4 cups milk
12 oz. sharp cheese, grated
Salt and pepper
Paprika

Boil potatoes until cooked but still firm. Cool; then grate into buttered casserole dish. Mix in grated onion. Melt butter in saucepan, stir in flour and milk to make white sauce. Add grated cheese, season to taste and pour over potatoes. Sprinkle top of casserole with a little grated cheese and paprika. Bake at 350°  F. for 30 minutes or 325°  F. for 45 minutes.

Serves 6-8.