Scrub and dry your potato. Using the large holes of a box grater, grate the potato over a piece of cheesecloth. Squeeze liquid from the grated potato, and add to a medium bowl.
Grate the onion and add to the potatoes.
Add egg, salt, and, pepper, and stir completely to combine.
Add oil to a saute pan set over medium heat. You'll want enough so these truly fry and don't just saute: be sure that there is about 1/4 inch worth of oil in your pan.
Form spoonfuls of the batter in your hand, patting the mixture to form 2-2/12 inch wide pancakes. Add directly to the hot oil.
Fry on both sides until golden brown, about 3 minutes per side.
Serve warm with sour cream and apple sauce for serving.