For long-fermented rolls, prepare the dough at least 7 hours before baking. Overnight is best for Christmas morning.Cut the butter into the flour until it looks like fine sand. Mix in the starter, sugar and milk until a soft dough ball just comes together. Cover and put in a warm spot overnight.Preheat oven 400 degrees F.Combine salt, baking powder and baking soda in a small bowl and sprinkle over the dough.Knead the salt/baking powder/soda gently into the dough ball along with a little more flour until a smooth dough ball is formed. Be careful not to over knead the dough.Roll out the dough until it is about ¼" to ½" thick in a large rectangle.Spread filling evenly over the dough.Starting along the long edge, roll up the dough tightly into a long roll. Use both your hands to roll it evenly and as tightly as possible.Cut the roll into ½" thick slices.Place slices into a well greased cast iron skillet or cookie sheet and bake for 20 to 30 minutes until golden brown.