Whisk together flour and salt. Put the flour-salt mixture with diced butter in a food processor. Pulse 3-4 times, to uniformly disperse the ingredients. Gradually pour water and pulse 7-8 times to form shaggy mass. Dump the mixture on to a cool work surface and lightly knead to form dough. Add some water, if the ingredients are dry. Shape the dough into a 5x5-inch square and wrap in a plastic. Refrigerate the dough for at least 30 minutes.

Wrap the cold butter in a plastic and pound it with a rolling pin to soften the butter. Shape the butter into a 5x5-inch square and let rest at room temperature.

Unwrap the cold dough on a lightly floured work surface. Dust the rolling pin with some flour and roll out the 4 corners of the square in a center-to-edge motion. Let the center be thicker than the rolled out flaps. Place the butter square in the center of the dough and fold the flaps over the butter. Lightly pinch the edges to seal.

To make a Single Turn: Start from the center-to-edge and roll the dough into a rectangle sheet 1/4-inch thick. Use flour to dust as needed and do not roll over the edges. Make a letter fold; top-down: bottom-up.

Turn the dough 90 degrees, roll into a rectangle and repeat the single turn (previous step). When you make two single turns, wrap the dough in a plastic and refrigerate for at least 30 minutes.

Form two more single turns, wrap the dough and refrigerate for at least 30 minutes.

Again, form two more single turns, wrap the dough and refrigerate for at least 30 minutes.

By now you have created six single turns or: {(3 x 3) x (3 x 3) x (3 x3)} = 729 layers.

After the dough is well relaxed in the refrigerator, you can either process it further or double wrap and freeze the dough for up to six months. If the dough is frozen, thaw it by refrigerating over-night.