Directions

To make the pastry, in a large bowl whisk together the two flours, salt, and sugar. Add the cold butter all at once to the flour mixture and use your fingers to fluff and combine, coating all the butter.
Use your fingers to break the butter down into the flour. Press the butter chunks between your thumb and index fingers into rough sheets of butter.
Break all of the butter pieces down, creating pea size chunks of butter along with flattened sheets of butter. This usually takes me about 5 to 7 minutes. Work quickly as to not heat the butter with your hands too much.
Make a well in the center of the flour and butter mixture. Stir together cold water and vinegar. Add 3/4 of the liquid to the flour. Mix the flour mixture towards the center, tossing together the wet and dry ingredients. Add more of the water mixture as necessary to create a moist but still fairly dry dough. Dump the dough out onto the counter and start to gently knead together into a thick rectangle. Add more water as necessary and you'll know you have enough liquid when there are no dry patches remaining.
Wrap the dough in plastic wrap and chill for at least 1 hour, or overnight.,Once the dough is well chilled, remove it from the refrigerator and place on a well floured counter. Roll the dough into a 1/2-inch thick rectangle roughly 6x16-inches wide and along.
Position the rectangle the long way from where you stand extending out long in front of you. Fold the bottom third of the dough up towards the center. Fold the top third of the dough down over the first fold. This is a letter fold we'll repeat.
Rotate the dough a quarter turn clockwise so the ends of the folds are facing towards you and away from you. Roll the dough out long into a 1/2-inch thick rectangle again so that it extends long out in front of you. Fold into the letter fold once again. Rotate and roll and fold once again.
Complete 4 roll and fold laminations. You may need to return the dough to the refrigerator to rechill the butter in the middle of working. Cold butter is best.
After the 4th fold, divide the dough in two. Wrap the dough in plastic wrap and refrigerate for at least 2 hours or overnight.