Sourdough Irish Soda Bread   Sourdough Irish Soda Bread Ingredients 4 cups all-purpose flour 1/3 cup sugar 1 teaspoon baking soda 1 teaspoon salt 8 tablespoons (1 stick) cold butter, cut into small pieces 1/2 cup currants zest from one large orange 1 cup sourdough starter 1 cup plus 2 tablespoons buttermilk Cooking Directions Preheat