In a large bowl whisk together the flour and the salt. Then mix in the water about a third of it at a time. As the dough comes together knead it with your hands, adding extra water or flour as necessary to wind up with a slightly tacky dough.Then place the dough on a floured surface and a bit of flour to the top and knead until the dough is no longer tacky. Shape and roll out the dough into about an 8x8 inch square. Wrap it tightly with plastic wrap and chill it for 30 minutes.
Set the butter out around 20 minutes before starting. Cut it into cubes/chunks and place on a floured surface or parchment paper. Pound and fold the butter and shape it until you have a 5x5 inch square slab. Wrap it with plastic wrap or parchment paper and chill it with the dough.
Remove the dough and butter from the plastic wrap. Roll out the corners of the dough a little bit to created flaps. Place the butter slab in the middle of the dough with the edges of the dough pointed towards the corners or dough flaps. Fold up those flaps enveloping the butter into a nice pouch. Pinch any seams together.
Flip the dough over, seam side down, and roll it out until you have roughly an 18x10 inch rectangle, it doesn't have to be exact. Then fold it into thirds. Flip it over, seam side down and roll it out again and then fold. That gives you two folds.
Wrap the dough in plastic wrap and chill it for 30 minutes. Now just repeat the steps of rolling and folding and chilling, until you have done 6 total folds. Roll out the dough once again until it is flat and then use it for whatever recipe you want. Easy as that.
To bake it, cut it into your desired shapes, baste it with butter or an egg wash, and place it on a silicone mat or parchment paper-lined baking tray and bake in a preheated oven at 375 F/190 C for 22 to 26 minutes until it puffs up and gets nice and golden brown.