If your mother is from Ireland, you know about soda bread, baked daily in many homes both in Eire and abroad. Owners Martin Lynch and John Clarke remember, and that's why with every meal at this venerable pub a basket of the tasty quick bread is set down on the table just after the pint of Guinness. The formula is simple: flour, salt, soda, buttermilk, and a handful of raisins. And you don't have to be Irish. Lynch says people with surnames like Castillo and Cohen come in all the time just for the bread. You can carry some home, too, for $3.50 a loaf.