If using store bought pastry dough, roll the dough into an 18 x 21-inch rectangle then proceed to step 13.
Using a mixer, mix the flour, salt, and water until a soft dough that pulls away from the side of the bowl, about 30 seconds.
Dust the work surface with flour. Roll the dough into a 6x6 inch square.
Flour the top of the dough and cover with plastic wrap. Let it rest at room temperature for 15 minutes.
Roll the dough out into an 18-inch square.
Brush the excess flour off the top of the dough and trim off any uneven edges.
Starting with the left side, spread butter on 2/3 of the square, leaving a one-inch unbuttered space at the 4 edges.
Neatly fold the unbuttered right side of the dough over. Brush off any excess flour then fold over the left 1/3 of the dough, similar to a tri fold.
Press the dough lightly from the top down to releaseany trapped air bubbles.
Pinch the unbuttered edges of the dough to seal it. Brush off any excess flour.
Turn the dough so the fold is facing you. Lift the dough and flour the work surface.
Once again roll the dough out into an 18-inch square, then repeat steps 5 to 9. This folding will create the flaky layers.
Turn the dough again so the top fold faces you.
Roll the dough out into 18-by-21-inch rectangle. Spread the remaining butter over the entire surface of the dough.
Using a spatula as an aid, lift the edge of dough closest to you and roll the dough away from you into a tight log, brushing the excess flour from the underside as you go.
Trim the ends and cut the log in half. Wrap each piece in plastic wrap and chill for 2 hours or preferably overnight.