1. Peel the potatoes and shred them in a food processor fitted with the shredding blade. Transfer the potatoes to a large bowl as the food processor fills up. Repeat the same step with the onion.
2. Combine the potatoes, onions, egg, baking powder, salt and matzo meal.
3. Fill a large skillet with ½“ oil. Heat over medium heat until the oil is very hot but not smoking. To test to see if the oil is hot enough drop a small piece of potato in the oil, if the potato sizzles the oil is ready.
4. Working in batches scoop the potato mixture by ¼ cupful into the hot oil, flattening each latke slightly with a spatula. Fry turning the latkes once until golden brown and cooked through about 3 minutes. Drain on paper towels.
5. Serve with sour cream and applesauce.