A 'farl' isn't a recipe — it's a shape: the word simply means a quarter, from how the round of dough is cut into four triangles before it hits the griddle.
Buttermilk soda bread dough is patted into a round, cut into quarters, and cooked on a dry flat griddle until the outside is browned and the inside stays soft, then often fried again in bacon fat for an Ulster fry. Market cafes and takeaway vans serve the wedges split and buttered, or stacked into a fry-up roll.