Wash and dry the potatoes, peel, then coarsely grate on a box grater or use the shredding blade of a food processor. Squeeze as dry as possible. I suggest placing in a colander and using your hands to press down as hard as possible, draining away any liquid. Then use a clean kitchen towel or several layers of paper towels to wring the potatoes dry over the sink. You might have to change towels or paper towels a couple of times to get them really dry. Don’t skip this step; it helps the latkes be as crisp as possible.

Place dried grated potatoes in a large mixing bowl and stir in chopped scallions and season well with salt and pepper.

Position rack in middle of oven. Preheat the oven to 300°F/150°C. Place a rack on a half sheet baking pan and set aside. Also have several layers of paper towels near the stove to receive the pancakes as they emerge from the oil.

Heat about 2 inches (5 cm) of vegetable oil in a heavy straight-sided skillet over medium-high heat (do not use nonstick). Drop a few shreds of potato in the oil; they should sizzle. If you want to use a deep-fry thermometer, the oil should be about 350°F/180°C.

Use a 1/4 cup (60 ml) measuring cup to scoop up potato mixture. Drop mound of potatoes in oil and immediately press down firmly with spatula. The latkes should be about 3 inches (7.5 cm) across. The number you can cook at a time depends on size of skillet; do not crowd them in the oil. Typically 3 or 4 at a time is a good number to keep track of.

Fry until well browned and crisped on the bottom, about 2 to 3 minutes, adjusting the heat as necessary. Flip the pancakes over and cook on the second side until well browned and crispy. Drain on paper towels, then place on the prepared rack and keep warm in the oven as you fry the remaining latkes. Serve as soon as possible, with an optional sprinkle of flaked salt (my choice!) and/or also offering lactose-free sour cream, if desired.