Mix flour and salt in a bowl. Add the sourdough and mix it in with a spoon or your fingers until it's evenly dispersed.

Cut the cold butter into small cubes and add to the bowl. Cut it into the flour with a fork or pastry cutter.

Drizzle in ice cold water and mix with a fork until the dough comes together. Try not to overmoisten--add just a little water at a time.

Divide the dough in two. Place each half in a piece of cling wrap and, as you wrap it, shape it into a disc. Try not to handle the dough with your hands because you don't want the butter to melt. Refrigerate the discs of dough for at least half an hour before you are ready to use them. Your pie dough is now ready to use. Or, for a more layered, puff-pastry-like crust, see additional directions belpw.

Take one disc of the refrigerated dough and roll it out on a floured surface to a rectangle approximately 10 inches long and eight inches wide.

Flip it over so the floured side is facing you. Fold the rectangle as you would puff pastry--bring one edge up and to the middle, and then fold the other edge over it.

Flour the surface, then roll out the dough again to a rectangle 10 by 8 inches. Flip over and once again fold the pastry as described above. Repeat two more times. Wrap the folded dough in cling wrap and refrigerate again for at least 30 minutes. When making the pie, remove from the fridge and roll out as you would pie dough.