What is the best way to prepare scalloped / au gratin potatoes?
Scalloped and au gratin potatoes are baked “en casserole” and made from peeled potatoes combined with flavored heavy cream, white or cheese sauce, or uncooked custard, then slowly baked until potatoes are extremely tender.
For best results, use 100 – 70 count fresh Idaho® Potatoes.
Slice Idaho® Potatoes 1/8-1/16″ inch thick. If you preslice the potatoes, acidulate them in water with lemon juice; then dry, cover, and refrigerate to prevent browning. Layer potatoes in a buttered hotel pan and add heated cream, sauce, or custard. Shake pans to distribute ingredients evenly. Cover loosely with foil, then bake in a moderate oven (325-350°F) until tender, about one hour.
Remove foil and brown as desired. For au gratin potatoes, top with bread crumbs, butter, and grated cheese after baking, then brown. The potatoes should be tender but hold their shape when portioned, and the sauce should be smooth and uncurdled. (Bake potatoes in a water bath to prevent curdling.) For most attractive portioning, hold potatoes for 10 minutes before serving.
En casserole dishes hold longer than boiled or baked potatoes. Cover dish loosely with foil and hold in a warm place through a typical service period, about two hours. If necessary, reheat in the oven or brown lightly under a salamander or broiler.
For quick scalloped potatoes, mix flour, salt, pepper, and milk, then pour over potatoes and bake for one hour. The long baking time dissipates the flour taste. For a low-fat version, mix skim milk, potatoes, garlic, salt, and pepper and simmer until potatoes are nearly cooked. Dilute arrowroot with a little cold milk (1/2 oz. arrowroot to 2 quarts of milk) and add to simmering potato mixture. Stir until thickened and pour into a hotel pan sprayed with cooking spray. Sprinkle bread crumbs and Parmesan cheese on top. Bake at 350°F until brown.