Published March 1, 2007.
Achieving a crisp crust and creamy—not gummy—interior is easier said than done in this simple Swiss potato cake.
Despite the simplicity of the recipe—grated potato seasoned with salt and pepper and fried in butter—roesti often has a gummy interior and a soggy, bland exterior.
We wanted a crunchy, crisp exterior encasing a tender, creamy interior tasting of little but earthy potato and, of course, rich butter.
Our first two decisions were easy. We wanted to start with raw potatoes, since cooked potatoes must be cooled overnight to prevent crumbling when grated. And we chose Yukons over other potato types for their buttery flavor and sunny complexion, which emphasized the final caramel-colored crust. But figuring out the best cooking technique was a challenge. Producing a golden-brown crust wasn't much of a problem, but the inside always came out gluey and half-cooked. To solve the issue, we combined several techniques. We eliminated moisture by wringing them in a towel rather than patting them with a paper towel. We also needed to initially shape the grated potatoes into a cake rather than pack them tightly into the pan. Initially covering the potatoes then uncovering them to finish cooking created surprisingly light potatoes. Our final breakthrough came after studying the challenge posed by the potato's starch. We first needed to remove excess starch with a rinse in cold water before squeezing, but then needed to add back just enough starch to hold the patty together, so we tossed the rinsed, squeezed-dry grated potato with a teaspoon of cornstarch.
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