Start by shredding the peeled potatoes using a box grater, then place the shredded potatoes into a large bowl.
Use a clean towel or cheesecloth to squeeze out as much excess moisture from the shredded potatoes as possible. This helps ensure the fritters turn crispy and not soggy.
Add the finely grated onion, salt, and freshly ground black pepper to the bowl of drained potatoes.
Stir in the flour and beaten egg until everything is evenly combined, creating a sticky mixture that holds together well.
Heat the oil in a frying pan over medium-high heat until shimmering and hot—test with a small drop of batter; it should bubble immediately.
Using a tablespoon, scoop out a portion of the mixture and gently shape it into a flat patty about half an inch thick. Carefully place it into the hot oil, making sure not to overcrowd the pan.
Fry the fritters for about 3-4 minutes on each side, or until they are deep golden and crispy around the edges, listening for a gentle crackle as they cook.
Use a spatula to flip the fritters carefully, ensuring they keep their shape and develop an even crust.
Once golden and crispy, transfer the fritters to a plate lined with paper towels to absorb excess oil. Rest for a minute to finish crisping.
Serve the fritters hot, garnished with herbs or a squeeze of lemon if desired, and enjoy their crispy, fluffy texture.