Place potato chunks and onion in a blender or food processor, with enough to get the machine going. Process until finely broken down. Add lemon juice and pulse in.
Place mixture in a sieve over a bowl, making sure bowl is deep enough so there’s about two inches room between the bottom of the strainer and bowl. Cover the top of the potatoes with a little paper towel or plastic wrap.
Let potato mixture drain for 10 to 15 minutes. When ready to cook, remove the strainer and slowly dump out the liquid in the bottom of the bowl, leaving the thicker, starchier mixture behind Add potato mixture and salt to the starchier mixture left behind in the bowl.
Heat pan until oil is shimmering. Add potato mixture, using 1/4 of it for a larger potato pancake or in heaping tablespoons for appetizer size. Gently press down to about 3/8ths of an inch thick. Cook until golden brown before turning. Take your time and turn the heat down a bit if needed; the entire cooking process should take about 10 minutes.
To turn the larger pancakes, loosen with a thin spatula, quickly drain off excess oil into a small bowl (you’ll add it back in), place a plate over the skillet, and turn over skillet and plate together.
Put the skillet back on the heat, add the oil back in and slide the pancake back in to finish cooking. When finished, drain on paper towels or a paper bag. Serve hot with dipping sauce.
Notes: