In a mixing bowl, combine flour and baking powder. Add zucchini, egg, and onion, and mix to form a thick batter. Season with Salt and Pepper.
Heat oil in a fry pan over medium-high heat. Carefully drop large spoonfuls of batter into pan, spacing fritters an inch apart, and flatten slightly. Fry for 2–3 minutes per side, until golden brown. Cook remaining zucchini fritters, adding more oil to the pan if necessary.