Scrub potatoes and onion, then shred them using food processor or manually using a grater.
Wring out as much liquid as possible, reserving liquid in a separate bowl. Work batter in batches. Use a cheesecloth or thin produce bag to help you wring out excess liquid. Add potato-onion mixture to a seperate bowl and set aside.
Dispose of liquid in your sink, however, reserve the bottom white starch left behind. Add the starch back into your potato-onion mixture.
Add eggs, flour, salt, baking powder and pepper to potato-onion mixture and mix well.
Heat a generous layer of oil in a heavy-bottom pan or electric skillet. The oil is hot when you put a single potato strand into the oil and it sizzles. Add latkes by the spoonful (to desired size and thickness) to skillet or pan, careful not to overcrowd.
Cook on each side for 2-3 minutes until browned, then flip to brown on other side. Remove latkes to a paper towel-lined plate. Repeat process until all batter is cooked, adding more oil as needed.
Serve latkes immediate with applesauce and/or sour cream.
This recipe makes about 16 large latkes or 25 small latkes.