If you have a sourdough starter, this is a way to significantly improve the flavor of homemade bisuits. For this recipe, feed your starter with equal weights of flour and water for a very thick batter consistency.
In a bowl, add buttermilk to the starter and stir well to break up and dissolve the starter.
Add the flour to a large, clean bowl and grate the butter into the flour stirring often or cut the butter into small pieces and mix with the flour using a pastry blending tool or a fork. Add the buttermilk mixing in more and more flour until all the flour is involved and the dough is sticky, gummy and on the verge of being "too wet". Add additional buttermilk if needed or flour.
Turn out the dough onto a floured surface and with flour on your hands make into a very soft dough, sprinkling a little extra self-rising flour over it all as needed until no longer sticky. Try not to work the dough at all or anymore than necessary for it to be consistent throughout. Pat out dough to 1/2-inch thickness.
Cut with floured 2 1/2-inch round cutter. Place on cookie sheet or greased cast iron skillet.
Bake at 450°F for 15 minutes or until golden brown. Brush with melted butter if desired and serve warm.