Place flours, salt and sugar in work bowl of food processor. Pulse briefly to mix. Add the butter, cut into small bits. Pulse the mixture until the butter is evenly distributed, and about the size of small peas. Alternately, the dry ingredients can be mixed in a bowl and the butter cut in with a pastry blender. Add the milk gradually, stirring gently to make soft dough; if additional is needed, add by the tablespoon until the consistency is right. Turn out onto a lightly floured surface and pat into a ½-inch thick circle. Cut into rounds of desired size (Mom’s were always substantial…) Bake in preheated oven for 15-20 minutes until golden.