Pare and peel potatoes. Grate immediately on 3/16" slot grater. Place grated potatoes on heavy duty paper towel and press out water.
Mix the grated potatoes with the grated onion.
Beat eggs well, then add baking powder, and flour. Mix well.
Add potato/onion mix to a large bowl. Pour egg mixture over the potato and onion mix, and mix wel lby hand.
Heat half of the olive oil in a skillett until hot (when a drop of water sizzles).
Form potatoes into 3-4 inch wide by 3/8 inch high patties and add to the skillet via a spatula. (Don't drop the potato pancake directly to avoid splashin g the hot oil).
Add more potato pancakes as space allows.
Cook the potato pancake until golden brown on one side, then flip and cook the other side until brown.
Add more olive oil as needed between batches.
Place pancakes in a 200-255° oven to stay warm until all are done. Cover loosely with aluminum foil if desired but don't cover tight as the potato pancakes will become mushy.
Serve hot with sour cream, applesauce, ketchup, etc.