Don't confuse this bread with Irish soda bread, which is studded with raisins or currants. This one gets its name from the fact that baking soda is used as the leavener, instead of the more usual yeast or baking powder. It also is made moist with the addition of buttermilk instead of regular milk; here, you make your own version by mixing regular milk with lemon juice and allowing it to thicken and curdle and take on the qualities of the real deal.