Mix eggs, flour, baking powder, salt, and pepper in a big bowl. Then, add potatoes and onion.
Warm up oil in a big frying pan on medium heat. Place large spoonfuls of potato mixture into hot oil in small groups. Push to make flat. Cook until golden and crunchy, approximately 3 minutes on each side. Move to a plate with paper towels to remove excess oil. Repeat with the rest of the potato mixture.