Preheat oven 425
Mix dry ingredients-flour, salt, baking powder, and soda
Slice butter, or use grater and with a fork or pastry cutter, crumble butter into dry ingredients leaving chunks of butter.
Add sourdough and mix until well combined. add extra flour if dough is sticky.
Oil an iron skillet with your choice of oil. I like to use bacon fat
Pinch off a good round of dough, flatten, dip both sides in grease and place in skillet. repeat until all biscuits are crammed in there.
Bake at 425°F for 15-18 min