5 pounds russet potatoes, scrubbed but not peeled
2 large bunches scallions, finely minced (set a few spoonfuls aside to garnish the finished latkes)
8 cloves garlic, minced or pressed
2—3-inch knob fresh ginger, grated
1 tablespoon salt
1/2 teaspoon ground white pepper
1 tablespoon toasted sesame oil
1/4 cup matzo meal
1-2 cups high-heat oil for frying
1 cup sour cream
1 tablespoon rice wine vinegar
toasted sesame oil
Line a strainer with a large piece of cheesecloth or a loose-weave dish towel, and place in the sink or over a bowl. Shred half of the potatoes on the coarse holes of a box grater, and place the shreds in the lined strainer (if you have a food processor with a shredding disk, use that instead, then place about 1/4 of the shreds back in the bowl with a chopping blade, and pulse a few times to yield smaller bits that will help bind).
Pick up the ends of the dish towel or cheesecloth and gather it around the load. Twist and squeeze to wring as much liquid as possible from the mixture, twisting further as more liquid is released. When it's as dry as possible, place the wrung-out mixture in a large mixing bowl. Repeat with the remaining potatoes.
Add the scallions, garlic, ginger, salt, pepper, eggs, sesame oil and matzo meal to the potatoes, and stir well to combine. Pour the oil into frying pans to a depth of 1/2 inch, and heat over a medium-high heat until a shred of potato sizzles when dropped in. Shape three tablespoons of the latke mixture into a round shape (I like to pack a 1/4 cup measure three-quarters full) and place in the oil. Flatten slightly to form a small pancake. Repeat as many times as your pan space allows. Cook the latkes until they're well-browned, 5 to 7 minutes, then flip and brown the other side (play with the heat if it's taking much more/less time). When the second side has cooked, place on a plate lined with brown paper or paper towels, stacking with additional paper or paper towels as needed.
To serve, stir the rice wine vinegar into the sour cream (taste, and add more if you favor a bit more tang). Top each latke with a dollop of the tangy sour cream, a small drizzle of soy sauce and/or sesame oil, and a sprinkling of the reserved scallions. Serve.