Potato Puff
Prepare two and one-half cups hot mashed potatoes. Add two and one-half tablespoons butter, one-half teaspoon baking powder, season with salt and pepper and moisten with one-half cup hot cream or milk, beat thoroughly. Add the whites of two eggs beaten until stiff. Pile lightly in a buttered baking dish and bake until well puffed and browned.
A soufflé-style potato dish that depends almost entirely on how the potatoes are handled before the egg whites go in. The original gives no oven temperature or time, so those are the first gaps to fill.
- Oven and timingBake at 375F for 25 to 30 minutes, until risen and browned on top. A shallow dish puffs faster and more evenly than a deep one.
- The hinge: keep everything hotThe potatoes, butter and cream must all be hot when combined, and the folded whites must go into the oven immediately. A cooled, stiffened potato base will not lift the whites and the dish bakes flat.
- PotatoesUse a floury variety such as russet, riced or passed through a food mill rather than mashed with a masher. Never use a food processor; the starch turns gluey and no amount of beaten white will lighten it.
- Baking powderHalf a teaspoon in a mixture this wet does very little and can leave a faint metallic edge. The egg whites do the actual work and the powder can be left out.
- Cream or milkHalf a cup is right for potatoes on the drier side. If yours are already loose, add the liquid gradually — the base should hold a soft peak, not pour.
- Folding the whitesBeat to stiff but not dry peaks and fold in two additions with a spatula. Beating them in, as a literal reading of "add" might suggest, destroys the aeration.
- YieldAbout four side-dish servings from a 1-quart dish. Like any soufflé it settles within a few minutes of leaving the oven, so serve at once.
Potato puffs and potato soufflaand English household cookery in the later nineteenth and early twentieth centuries. The appeal was economy dressed up: leftover or freshly boiled potatoes, a little butter and cream, and two egg whites turn a plain starch into something that arrives at the table looking like a course. It is the sort of dish that can be assembled while a roast rests, using the same oven, and that makes a modest joint look better attended. The baking powder is a period touch, reflecting the era's enthusiasm for chemical leaveners, which were added to a great many recipes that did not strictly need them.