In a large bowl, combine the Pastry Flour and butter with your hands until a small crumb-like texture forms.

Add in salt and water one tablespoon at a time and combine with your hands until a rough dough forms. Water amounts will vary, but will be in the ballpark of 2/3 cup.

Turn out onto a floured surface and shape into a rectangular shape, wrap in plastic wrap and chill in the fridge.

Once the dough is chilled, turn out onto a floured work surface. Take the frozen grated butter out of the fridge. Spread 1/2 of the frozen grated butter out over 2/3 of the rectangular dough.

Fold the top down a 1/3 of the way over the butter, then fold the bottom up over that fold. It should make another rectangle where no butter can be seen.

Turn the entire new rectangle clockwise 90 degrees. Gently roll that rectangle out larger and add the rest of the frozen grated butter. Fold the top down 2/3 of the way, and the bottom up over that.

Seal up all the edges of the dough, making sure no butter is coming out. Gently roll out to a larger rectangle. Fold the top down 1/3 of the way, and fold the bottom up over.

Wrap the rectangular dough in plastic wrap and chill in the fridge for at least an hour.

After it has chilled roll it out on a non-stick surface and it is ready to use for your recipes that call for puff pastry.