After the dough has rested, prepare your dry butter.
Place the butter on one side a sheet of parchment paper. Using a rolling pin, beat the butter until it is soften, folding it over on itself three or four times when it starts to get too thin and start again. Your goal is to have the butter to be the same consistency as the dough.
Once the butter is the correct consistency, fold the parchment paper over the butter and fold in the sides, creating a closed square. Roll the butter into a flat sheet and be sure to roll into the corners.
Put the butter in the fridge for 10 minutes.
Take your dough out of the fridge and start to roll out into a long rectangle, large enough to fit the square of butter to fit in the middle and enough excess to on the top and bottom to fold over the butter.
Once the butter is cold again (it should be the same temperature as the dough, this is when a laser thermometer comes in handy), turn out into the middle of the rectangle. Fold the sides of the dough, joining the ends together in the center, enveloping the butter in dough. Use the rolling pin to close the ends of the dough, sealing the dough inside.
Flour the surface of the dough and ensure that there is enough flour underneath as well, so your dough will not stick. If it sticks, the dough will rip and your precious butter will leak out.
With the rolling pin, press down slightly every couple centimeters to keep the butter from sliding around. Start rolling out the dough in length (the length of your rolling pin).
Remove the excess flour with a pastry brush, divide into 3rds, folding the first 3rd, and then remaining end on top of the first fold. This is called a single fold. Seal the ends together lightly with your rolling pin.
Wrap and let chill in the fridge for 30 minutes
Dust the chilled dough with flour and press down every couple centimeters with your rolling pin, before rolling out in the opposite direction as you previously did.
Lightly roll lengthwise. It should be slightly longer than your rolling pin. Try to keep the same thickness throughout.
Do your first book fold (tour double). Fold both ends into the middle to meet, then fold in half. Cover and let rest in the fridge for 30 minutes
Roll out into a rectangle that is about 30cm x 40cm. Trim all of the edges, so you have straight lines. Transfer to the fridge while you prepare for the next step.