In the bowl of the food processor, add the flour, buttermilk powder, confectioners’ sugar, baking powder, and salt. Pulse several times until the dry ingredients are thoroughly distributed.
Cut the cold butter into small cubes (about ⅓ the width of a stick of butter) and add it to the dry ingredients. Pulse about 10 to 15 times, until the mixture is crumbly with uneven bits of butter.
Sprinkle the orange juice over the dough and pulse a few more times. Add the ice water 1 tablespoon at a time, pulsing until the dough clings together. If a piece of the dough holds together in your hand and doesn’t feel dry or crumbly, it’s ready.
Lightly flour a work surface and turn the dough out. Shape the dough into a round disk about 1 inch/2.5 cm thick and roll it on its edge in the flour to smooth the edges out.
Wrap in plastic wrap and put in the refrigerator overnight before using. Will keep in the refrigerator up to 3 days.