The next day begin the process of laminating your dough. Be sure to work quickly when handling the dough so that the dough and butter stay cold.
Take the unsalted butter and slice into pieces, forming a rough square. Place the unsalted butter between two pieces of parchment paper and roll out to a 7.5" square. Use a ruler to scrape the sides of the butter back to create straight edges. When the square is formed, return the butter block to the fridge and chill until cold.
While the butter is chilling, take the dough out of the fridge and transfer to a lightly floured counter. Roll the cold dough out into a 13" square.
Place the chilled butter square diagonally on top of the dough. Bring together the four corners of the dough to completely cover the butter.
Gently, but firmly, begin to the roll the dough out. Do not press or roll to hard which can squish the layers together. If the dough feels too tight and springs back when you roll it, then stop rolling and let it sit for a few minutes to rest before continuing. Flip the dough occasionally and roll it out on both sides.
Roll the dough out to a 10” by 18” rectangle. Flip the dough so that the seam from the butter block is facing up. Brush the excess flour off with a pastry brush and fold the dough three times. The first fold should cover 1/3 of the dough, then bring the other side up to cover the first fold. Brush off the excess flour then place on a parchment lined baking sheet. Cover with cling film and refrigerate.
Refrigerate the dough for 30 to 60 minutes between folds. Repeat the rolling and folding process two more times. Place the dough back in the fridge to chill for 30 to 60 minutes before shaping.