Au Gratin Potatoes, 50 servings with vegan variation
Old traditional not-low-fat recipe. Can be skinnied down with nonfat milk, reduced fat cheeses and omitting half or all of the butter. Can be made vegan with plain (not vanilla) soy milk, vegan margarine, rice Parmesan and soy cheese.
Serves/Makes: 2 12"x20"x2" pans or 4 9x13" casseroles, 50 side dish servings: triple this recipe to serve 100 as a main dish.
Ready in 60 minutes once potatoes are boiled.
12 pounds potatoes, bakers, not red/new
1 pound grated or shredded onion
Salt to taste, about 1 tablespoon
1 pound butter or margarine, OPTIONAL
1 pound grated Parmesan or Romano cheese
2 pounds grated cheddar cheese, sharp preferred
6 ounces buttered bread crumbs
1 gallon medium white sauce made with:
1 gallon whole milk, warmed but not boiling
2 1/4 cups (8 ounces) flour, may need a little more
1 pound unsalted butter or margarine for white sauce
1 tablespoon powdered dry mustard
1 1/2 tablespoon salt
White pepper (optional)
Boil 4 gallons of water (takes 40-60 minutes). At the same time, heat the milk for the white sauce
Peel if desired and cube the potatoes to similar sizes, add salt to taste, boil until just tender, DO NOT overcook. Drain well. Water may be saved for soup making.
Make the white sauce. Stir in the cheddar cheese, set aside.
Place one half the cooked potatoes in a layer in greased pans, dot with onions and optional butter, up to 1/2 pound. Sprinkle with half the Parmesan cheese.
Pour half the white sauce over the potatoes. Repeat with second layer. Sprinkle the bread crumbs over the top of the potatoes (extra grated cheese can also be sprinkled).
Bake in a preheated convection oven at 400 degrees for about 30-35 minutes, rotate the pans from top to bottom after 20 minutes. Allow 50 minutes in a regular oven. Double baking time and reduce heat to 350 degrees if white sauce is cold or casseroles have been refrigerated.
Making the medium white sauce
You have already heated the milk, see above. Melt the 1 pound of butter in a 6 quart saucepan or Dutch oven. Remove from heat and add the flour; stir until smooth. Add salt and dry mustard. Add the hot milk gradually, whisking constantly. Return to medium heat, cook and whisk until smooth and simmering with bubbles at the edges. Keep it bubbling to thicken the sauce, but keep stirring. This will take about 15-20 minutes.