Grate potatoes and onion into a bowl or pulse in food processor. Drain any excess liquid, then add the eggs, matzo meal, salt and pepper.
Heat a large skillet over medium-high heat. Spoon the mixture into hot oil forming small pancakes. Cook until underside is golden, about 2 to 3 minutes. Flip pancakes and cook until other side is golden and potatoes are cooked through, about 2 minutes more. Serve hot with sour cream or applesauce.