Preheat heavy based flat griddle or skillet on medium to low heat.
Place flour and salt in a bowl and sift in baking soda. Make a well in the center, and pour in the buttermilk.
Work quickly to mix into dough and knead very lightly on a well floured surface. Form into a flattened circle, about 1/2 inch thick and cut into quarters with a floured knife.
Sprinkle a little flour over the base of the hot pan and cook the farls for 6 to 8 minutes on each side or until golden brown.
