5-6 medium Russet potatoes (about 2 pounds), scrubbed and cut lengthwise into quarters
½ large onion (8 ounces), peeled and cut into quarters
2 large eggs
½ cup matzo meal
2 teaspoons kosher salt, plus more for sprinkling
½ teaspoon freshly ground black pepper
Neutral oil, for frying
Fishwife Smoky Trio, flaked, for garnish
Sour cream, for garnish
Fresh chives, for garnish
Fresh salmon roe, for garnish
Preheat oven to 200F.
Grate the potatoes and onion on the large holes of a box grater or with the shredding disc in the bowl of a food processor. Transfer the mixture to a clean dish towel and squeeze and wring out as much of the liquid as possible. Discard liquid.
Transfer the potato mixture to a large bowl. Add the eggs, matzo meal, salt, and pepper, and mix until the matzo meal is absorbed.
In a large cast iron skillet over medium-high heat, pour in about ¼ inch of the oil. Once the oil is hot, drop about 2 tablespoons batter into the hot pan, cooking in batches. Use a spatula to flatten and shape the drops into discs. When the edges of the latkes are brown and crispy, about 5 minutes, flip. Cook until the second side is deeply browned, about another 5 minutes. Transfer the latkes to a cooling rack set over a sheet pan to drain and sprinkle with salt while still warm. Keep warm in preheated oven. Repeat with the remaining batter.
Top with sour cream, flakes of tinned fish, salmon roe, chives, flaky salt, and black pepper. Serve immediately.