06/16/14 For best success with the roaster, you will parboil the potatoes and make a white sauce for the cheese. My favorite method of making, where you just layer in the potatoes, onion, cheese, flour, and pour the milk over, does not do so well in the roaster.

An 18-quart roaster can comfortably hold 12 quarts of the casserole, roughly equal to five 9- by 13-inch casserole dishes. This takes approximately 25 pounds of potatoes and serves around 60.

Grease the roaster and line it with foil or parchment paper if desired to minimize cleanup If you grease, you can dust with plain old grated Parmesan to add to the flavor at the edges.

Assemble the recipe in the roaster's cooking pan.

For 25 pounds of potatoes you need about 5 quarts of medium white sauce heated with the cheese or Velveeta (2 1/2 to 4 pounds) added and melted.

Many people either grate some onion among the layers, or grated some onion into the butter for the white sauce before adding the flour.

Preheat the empty roaster to 350 for about 20 minutes. Then place the pan in the roaster, cover and bake for approximately an hour and a half until the casserole is bubbly and thickened, and the potatoes are tender.

If the potatoes are raw, it can take 3-4 hours.

If the potatoes were pre-assembled and refrigerated in the sauce, or the sauce is cold, it can add an hour to the cooking time. Check for doneness- a skewer goes into the middle easily, all the way to the bottom, and a quick read thermometer is at least 165, up to 180. When it is, turn the roaster to 180 to hold.

What you don't get is crispy edges and top. You can run the done dish under the broiler, if you can lift it- carefully, it is HOT< HOT< HOT! Or sprinkle on crushed French fried onions. Or just don't worry about it.

Some people make this a meal by adding 1 pound of meat (cubed ham, cooked chicken or meatballs) for each 5 people, for this recipe, 12-15 pounds.

Variations?