In a medium bowl, combine the flour, soda, salt and baking powder. Cut in butter with pastry blender until mixture resembles coarse meal.

In a small bowl, combine starter and buttermilk, mix into butter and flour mixture with a fork to form a soft dough. Turn out onto a floured surface, knead lightly for 30 seconds. Roll out to 1/2 inch thick and cut with a 3 inch cutter. Place on a greased baking sheet and brush tops with melted butter. Cover loosely with plastic wrap and put in a warm place to rise for 30 to 45 minutes. Bake at 425º for 12 to 15 minutes or until golden brown. Serve immediately

Makes about 15 biscuits.