In a bowl, combine the butter and sugar and blend to make a paste. Add the yolk and blend thoroughly. Add the flour and using your fingers, blend to make a crumbly dough, being careful not to overwork. Pat firmly into a 9-inch pie pan and let rest in the refrigerator at least 2 hours or overnight. Remove from the refrigerator and prick the bottom of the crust with the tines of a fork. Place a sheet of parchment or foil in the pie tin and fill with pie weights, dried beans or rice and blind bake the crust in a preheated 400 degree oven for 10 minutes. Remove the pie weights and foil and bake for another 5 minutes or until light golden brown.