In large mixing bowl, combine 1 ½ cup flour, yeast, sugar, salt and baking soda; mix well. In saucepan or microwave-safe dish, heat buttermilk, water and shortening/butter until warm (120-130°F; shortening/butter does not need to melt). Add to flour mixture; mix with dough whisk or wooden spoon until blended. Gradually stir in enough remaining flour to make a soft dough. Turn out onto lightly floured surface; knead for about 5 to 8 minutes or until smooth and elastic. Use additional flour if necessary. Place in greased bowl, turning to grease top. Cover; let rise in warm place until light and doubled, about 20-30 minutes.Punch down dough. Divide into 4 equal parts. Divide each fourth into 6 equal pieces. Shape each piece into a smooth ball. Place in greased 15x10-inch jelly roll pan. Cover; let rise in warm place until almost doubled, about 20-30 minutes. Bake at 400°F for 15 to 20 minutes until golden brown. Remove from pan and place on wire rack to cool.