In large mixer bowl, combine 1 cup flour, yeast, sugar, salt and baking soda;
In saucepan, heat buttermilk, water and shortening until warm (120 to
130 degrees F); shortening does not need to melt). Add to flour mixture. Blend at
low speed until moistened; beat 2 minutes at medium speed.
By hand, gradually stir
in enough remaining flour to make a soft dough.
Knead on floured surface until smooth,
about 2 minutes.
Press dough evenly into greased 9-inch square cake pan. Sprinkle
top of dough lightly with flour. With table knife, cut dough into 12 rolls, cutting
almost to bottom of pan. Cover; let rise in warm place for about 20 minutes.
Bake at 400 degrees F for 15 to 20 minutes until golden brown.