Feed your sourdough starter the day before beginning the recipe
In a medium size mixing bowl mix ½ cup of fed active sourdough starter with 1 cup of the flour and one cup of room temperature whole milk.
Cover the bowl and place in a warm area for 4 to12 hours. The sponge will increase in size and possibly deflate depending on the amount of time you have left it to rise. If planning to bake the biscuits for dinner time you should start the sponges 8 hours before you plan to bake. The biscuits are best served hot straight from the oven.
After the sponge has proofed mix the sugar, baking powder, baking soda, salt and 1 ½ cups of the all-purpose flour into the bowl of sourdough sponge with a wooden spoon. Mix the dough into the sponge until it comes together shaggy dough ball.
Dust a work surface with the remaining ½ cup of flour. Turn the sourdough biscuit dough out onto the floured surface.
Before beginning to shape the biscuits brush the pan with 1 tablespoon of melted butter.
Flour your hands and gently knead the dough a few times so it holds it shape. Work the dough into a 12 inch long log.
Pinch off a one inch section of the dough and form into a roll. If the dough is sticky roll it in the flour before forming it into a ball.
Place each of the biscuits into the buttered pan snugly together with the sides touching.
Melt the remaining tablespoon of butter and gently brush each biscuit top with the butter. Cover the pan and place it in a warm area to rise for thirty minutes. After 15 minutes preheat the oven to 375 degrees.
Once the dough has risen to about double remove the plastic wrap or towel and bake the sourdough biscuits on the middle rack of the oven for 25 to 30 minutes, or until golden brown and the biscuits have risen.
Brush the hot biscuits with more melted butter if desired.
Serve the biscuits immediately.
Makes 12 sourdough biscuits.