Step 1 Sift the rye and all-purpose flours, sugar and salt into a large bowl, adding back any bits of grain or other ingredients that may remain in the sifter.
Step 2 Cut the butter into half-inch pieces and add to the dry ingredients. Rub the flour-coated butter between your fingers, breaking it into smaller bits. Continue rubbing until the butter is in sizes ranging from peas to hazelnuts. The more quickly you do this, the more the butter will stay solid, which is important for the success of the recipe.
Step 3Add the vinegar and sprinkle a few tablespoons ice water over the flour mixture. Working from the outer edge of the flour, mix the ingredients with your hands just to moisten the flour. The dough needs to come together as mostly one lump, with a few shaggy pieces. Squeeze the dough together to see if a ball forms. If it is too dry to come together, add additional ice water, 1 tablespoon at a time.
Step 4Form the dough into a square, then wrap tightly in plastic wrap. Chill the dough in the refrigerator a minimum of 1 hour, preferably overnight.
Step 5Unwrap the dough onto a floured surface. Using a rolling pin, roll out the dough to form a rectangle about 8 1/2 by 11 inches. The dough will be crumbly and rough around the edges. Don't worry; it will come together during the rolling.
Step 6Fold the dough into thirds, like a letter. Turn the dough so that the seam is at the top. Again roll the dough into an 8 1/2-by-11-inch rectangle and again fold into thirds. Repeat again, then wrap the dough in plastic and chill for 1 hour or up to 3 days before using.