These delicious baked au gratin potatoes are one of my dad's speciality recipes! Creamy and delicious, these cheesy potatoes are great along any protein.
In a 13 x 9 inch baking dish, layer the sliced potatoes so they are in 3 rows.
In a medium sauce pan, melt the butter. Stir in the flour and cook over low heat for 3 to 4 minutes stirring until the flour and butter have thickened. Add 2 cups of the milk and the cheddar cheese. Stir for 4 or 5 minutes until cheese has melted. Add the remaining one cup of the milk, and stir for another minute.
Pour the milk and cheddar mixture over the potatoes. Add the shredded parmesan cheese and paprika on top.
Place baking dish in the oven and bake for 45 minutes or until potatoes are cooked through. To test if potatoes are cooked, pierce their centers with a fork. Then broil for an additional 2 or 3 minutes to brown the top.