Combine flour, baking powder, salt and soda. Cut in shorten until mixture resembles coarse crumbs. Add starter. Stir until dough clings together. Knead on a lightly floured surface 10 to 12 times. Roll out or pat to 3/4 inch thickness. Cut into 2-1/2 inch rounds. Place in an ungreased baking pan. Let rest for 10 minutes. Bake at 450F for 12 to 15 minutes.
Makes 10 biscuits.
Dissolve yeast in water in a large bowl. Add sugar and flour, mix well, add potato. Cover bowl with cheesecloth, let stand at room temperature 5 to 10 days until mixture has a fermented aroma. Stir 2 or 3 times daily.
To store, transfer starter to a jar. Cover with cheese cloth, refrigerate. Do not cover jar lightly with metal lid.
To use, bring desired amount of starter to room temperature. Replenish starter after each use by stirring 3/4 cup flour, 3/4 cup water and 1 tsp sugar or honey into remaining starter. Cover, let stand at room temperature at least 1 day or until bubbly. Refrigerate for later use. If starter isn't used within 10 days, stir in 1 tsp sugar or honey.
Repeat every 10 days unless replenished.
Cajun Country -- New Iberia, Louisiana