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1
Soak potatoes Peel potatoes and square off sides and ends.
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2
Cut lengthwise into 1/3-inch-thick slices, then cut into 4-by-1/3-by-1/3-inch sticks.
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3
Place in a large bowl and add cold water to cover by 1 inch, then let soak in the refrigerator at least 4 hours or up to 24 hours.
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4
Drain potatoes and spread on a clean kitchen towel and dry completely, patting off as much water as possible.
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5
Blanch potatoes in oil Line baking sheets with a double thickness of paper towels.
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6
Heat 2 inches of oil in a heavy stockpot over medium heat to 300F on a deep-fry thermometer.
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7
Working in batches and using a spider, lower potatoes into oil (the temperature will drop significantly, to about 270F, and slowly climb up again) and stir to separate.
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8
Cook just until softened (test one by breaking in half; it should be almost completely cooked through), but not brown, about 3 minutes.
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9
Use a spider or slotted spoon to transfer to one of the prepared baking sheets to drain, spreading in a single layer.
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10
Allow oil to return to 300F between each batch.
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11
(The potatoes can be blanched and left to drain on the prepared baking sheets for 4 hours in the refrigerator before finishing, replacing the paper towels as necessary.)
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12
Fry Heat oil to 350F.
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13
Again working in batches, add blanched potatoes to oil (the temperature will drop to about 340F) and stir to separate.
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14
Cook until golden brown, 4 to 4 1/2 minutes; if desired, add the rosemary and lemon zest during the last 20 seconds of cooking.
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15
Use a spider or slotted spoon to transfer to prepared baking sheets to drain (replace paper towels if you are using the same baking sheets as above).
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16
Allow oil to return to 350F between each batch.
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17
Serve Sprinkle with salt and serve immediately.
