Mashed and Pureed Potatoes

There are many different styles of mashed potatoes, but all of them involve cooking the potatoes whole or in pieces, crushing them to a more or less fine particle size, and lubricating and enriching the particles with a combination of water and fat, usually in the form of butter and milk or cream. Some luxurious versions may be almost as much butter as potato, or include eggs or egg yolks. Mealy types fall apart into individual cells and small aggregates, so they offer a large surface area for coating by the added ingredients, and readily produce a fine, creamy consistency. Waxy potatoes require more mashing to obtain a smooth texture, exude more gelated starch, and don’t absorb enrichment as easily. The classic French pommes purées, pureed potatoes, are made from waxy potatoes, pieces of which are pushed through a fine sieve or food mill and then worked hard—to the point of having what an eminent French cookbook writer, Mme Ste-Ange, called a “dead arm”—first alone and then with butter, to incorporate air and obtain the lightness of whipped cream. American recipes take a more gentle approach, sieving mealy varieties and carefully stirring in liquid and fat to avoid excessive cell damage, starch release, and glueyness.