Special equipment: 1 (16-inch) Dutch oven
Prepare the Sourdough Starter the night before. Preheat the oven to 400 degrees F.
Sprinkle yeast in the starter and stir. Add sugar and stir. Add salt and stir. Add baking powder and baking soda and stir. Add oil and then gradually add flour, stirring well after each addition. Place dough on a floured board and sprinkle more flour on top of dough. Flatten dough by hand to about 1/2-inch thickness and then cut with a biscuit cutter. Spray a 16-inch Dutch oven with non-stick cooking spray and then add a little oil to the bottom of the Dutch oven. Place biscuits in Dutch oven, being careful not to overcrowd them. Top with melted butter and set aside to let rise until wrinkles are gone, about 1 hour. Bake, with coals on the lid, for 25 or 30 minutes or until golden brown.
Dissolve yeast in warm water and whisk to combine. Add sugar and whisk until sugar dissolves. Add sifted flour, 2 cups at a time, whisking after each addition to combine. Peel, wash, and cut the raw potato into quarters; add potato to the flour mixture. Place starter in a large, deep bowl, cover it with a towel, and let rest in a warm place overnight. The starter should be made ahead of time, even 3 to 4 days ahead.
Recipe courtesy of Jean Cates and Sue Cunningham