To prepare the water dough, combine the flour, salt, water, and butter on medium speed with the dough hook attachment until completely blended, about 8 minutes.
Form the dough into a rough rectangle 8 by 24 in/20 by 61 cm and transfer it to a parchment-lined sheet pan. Press the dough into the sheet pan, wrap it tightly in plastic wrap, and let it relax under r