Using parchment paper, mark 5" by 5" square. Leave plenty of space to fold over. Slice the butter stick in four pieces lengthwise. Place on square and fold the parchment paper around it. Using a rolling pin, flatten it out to reach all sides and corners.
Repeat the same step, so you have two butter squares. Place in the fridge to firm up.
Next make the dough by putting the flour and salt in a bowl. Whisk it together. Then add cold butter in and crumble it with your hands to make the lumps smaller. Lastly add the cold water until a rough dough forms. Knead lightly to bring it together and wrap in plastic wrap or a container and put in the fridge for 30 minutes.
On a lightly floured surface, roll the dough to at least 12 inches by 6 inches. Place one butter square in the middle. Fold one side up and over the butter. Encase it completely in the dough, so no butter is peaking out. And then fold the other side down,
If it is too soft, put it in the fridge, but if it's fine, move on to the next step. Repeat the same process for the second butter square. Then put in the fridge for at least 1 hour.
Take the dough out and place on a lightly floured surface. Roll out as long as you can, but keep it 6 inches wide. Fold the top down 1/3 of the way down and then fold the bottom up 2/3 of the way up. Once they're lined up. fold in half like a book.
Wrap and chill for 2 hours. Then repeat the same step as before for the 2nd fold and 3rd fold. Remember to let it chill for two hours in between.
To use in a recipe, roll it out and cut into sheets. Bake at 400F for 10 minutes. Store leftovers in the freezer.