If using a food processor: Use the grating blade to shredd the potatoes and the onion. If shredding by hand, use a grater to shred all the potatoes. Dice the onion as finely as possible. Have ready brown paper shopping bags or paper towels for draining the oil from the latkes. You may also want to have the oven on at 200 F to keep the latkes warm until you’re ready to serve. If serving immediately then just have a baking pan covered with tin foil ready to keep the finished ones warm after they’ve been drained. In a large mixing bowl, using a wooden spoon or your hands (I use my hands, it’s faster) mix the potatoes and onions with the potato starch until the potatoes have released some moisture and the sornstarch is dissolved, about 2 minutes. Add the salt and pepper to combine. Add the matzoh meal and mix well. Set aside for about 10 minutes. The mixture should get liquid-y but sticky. In the meantime, preheat a large preferable cast iron but definitely non-stick skillet over medium heat, a little bit on the high side. Add about 1/4 inch layer of vegetable oil to the pan. The oil is hot enough when you throw a bit of batter in and bubbles rapidly form around it. If it immediately smokes then the heat is too high and you should lower it a bit. If the bubbles are really lazy then give it a few more minutes or turn the heat up a bit. With wet hands (so that the mixture doesn’t stick) roll into small golf ball sized balls. Flatten into thin round patties. I do about 4 to six at a time. Fry on one side for about 4 minutes, until golden brown. Flip over and fry for another 3 minutes. Transfer to the paper towels and proceed with the remaining latkes. Once latkes have drained on both sides, place in a baking pan to keep warm.