Delmonico Potatoes

A creamed potato gratin of the plainest sort, and the whole thing rests on the white sauce. Fifteen minutes in a hot oven only heats it through, so everything must go into the dish already cooked and already seasoned.

• Hot ovenBy the usage of the period this means roughly 400-450F. At that heat the crumbs brown in about the same time it takes the sauce to bubble at the edges.
• Medium white sauceBy the standard of this period, medium means 2 tablespoons butter and 2 tablespoons flour cooked together per cup of milk. Two cups of sauce therefore uses 4 tablespoons each and 2 cups milk. A thin sauce will flood the dish; a thick one sets like paste.
• CrumsAn older spelling of crumbs. Buttered crumbs are dry breadcrumbs tossed with melted butter, roughly 1 tablespoon butter to 1/2 cup crumbs, which is what allows them to colour rather than merely dry out.
• The potatoesUse boiled potatoes that are cooked through but still firm enough to dice without crumbling, and cool them before dicing. Waxy or all-purpose potatoes hold their shape; a floury baker will collapse into the sauce.
• Season the sauce, not the dishSeason the sauce -- salt and pepper are listed with no quantity, and the easiest place to judge them is in the white sauce, where they can be tasted and adjusted before the potatoes are folded in.
• If it goes in coldFifteen minutes assumes warm potatoes and hot sauce. From the refrigerator, allow 25-30 minutes and cover the top loosely for the first half so the crumbs do not scorch before the centre is hot.
• YieldTwo cups of potatoes with two cups of sauce fills a 1 1/2-quart dish and serves four as a side, three if it is the centre of a supper.
• Common variationOther versions of the dish stir grated cheese (1/2 to 1 cup) into the sauce, and some add chopped hard-cooked egg. Neither is in this text, but both are consistent with it.