Peel the potatoes and cut them into 4 pieces lengthwise so that they fit in a food processor fitted with a shredding/grate blade. Cut the onion similarly.
Grate the potatoes in the food processor and transfer to a bowl. Grate the onions and transfer to another bowl. Drain the grated potatoes in paper towels or cheesecloth to remove any liquid.
Place the potatoes and onion in a mixing bowl. Add the flour, salt, baking powder, pepper and eggs and mix to combine.
Heat the oil in a 12-inch frying pan over medium heat until hot enough for frying. Working in batches, drop serving spoon-size portions of the potato mixture into the pan to create oval latkes. Six should fit in the pan. Fry until golden brown, 10 to 15 minutes, then flip to cook the other side for 10 to 15 minutes as well.
Drain the latkes on paper towels after removing them from the frying pan. Keep warm in the oven until serving. The latkes can be reheated.
Sprinkle with chives and serve with sour cream or applesauce.