Begin by peeling the russet potatoes and the onion. Using a box grater or food processor, shred both the potatoes and the onion into fine pieces.
Transfer the shredded potatoes and onions to a clean kitchen towel or cheesecloth. Gather the ends and twist to squeeze out as much moisture as possible.
In a mixing bowl, combine the drained potatoes and onions with the all-purpose flour or Matzo meal, baking powder, sea salt, ground black pepper, and the large egg. Mix until well combined.
In a skillet or frying pan, pour a generous amount of vegetable oil or extra light olive oil and heat over medium-high heat.
Once the oil is hot, use a tablespoon to scoop the potato mixture and gently flatten it into a patty. Carefully place it in the hot oil.
Once the latkes are cooked, transfer them to a plate lined with paper towels to absorb excess oil. Sprinkle with kosher salt while they are still hot.
