Using a stand mixer fitted with the paddle attachment, mix together the flour, sugar, and salt for 10 to 15 seconds, or until combined.
Scatter the butter over the top.
Mix on low speed for 1 to 1 1/2 minutes, or just until the flour is no longer bright white and holds together when you clump it and lumps of butter the size of pecans are visible throughout.
In a small bowl, whisk together the egg yolks and milk until blended.
Add to the flour mixture all at once; mix on low speed for about 30 seconds, until the dough just barely comes together.
It will look really shaggy and more like a mess than a dough.
Dump the dough out onto an unfloured work surface; then gather it together into a tight mound.
Using your palm and starting on one side of the mound, smear the dough bit by bit, down the side and along the work surface (at Flour, it is called "going down the mountain"), until most of the butter chunks are smeared into the dough and the dough comes together.
Do this once or twice on each part of the dough, moving through the mound until the whole mess has been smeared into a cohesive dough with streaks of butter.
Gather up the dough, wrap tightly in plastic wrap, and press down to flatten into a disk about 1 inch thick.
Refrigerate for at least 4 hours before using.
The dough will keep in the refrigerator for up to 4 days or in the freezer for up to 1 month.