In a large bowl, combine the ground chicken, onion, garlic, egg, breadcrumbs, parsley, salt, and black pepper. Mix well until evenly combined.
Shape the mixture into small patties, about the size of a golf ball, and flatten slightly.
Heat olive oil in a frying pan over medium heat. Cook the rissoles in batches for about 4-5 minutes on each side, or until golden brown and cooked through.
Remove from the pan and drain on paper towels. Serve warm.