How to Make It
In a food processor, pulse the flour with the salt. Add the butter and pulse until the mixture resembles coarse meal. In a small bowl, whisk the egg yolk with the water. With the machine on, slowly add the egg mixture and process until the dough just comes together.
Turn the dough out onto a work surface and gather it together. Gently knead the dough 3 times, then form it into an 8-inch log or 2 disks. Wrap the dough in plastic and refrigerate for at least 1 hour or overnight.