Cut the butter into ¼-inch pieces (or smaller). I like to avoid using my hands too much. I use sharp knife and a plastic pastry scraper to hold the butter steady. First, slice it into matchsticks, then into little cubes. Scrape them onto a parchment-lined sheet pan, and pop them in the freezer for 15 minutes—just enough time to chill.
In the bowl of the stand mixer fitted with the paddle attachment, put 1 cup of flour and a teaspoon of salt. Turn the mixer on low and add the chilled butter a little at a time. Once all the butter is in, increase speed to medium and mix until butter is completely incorporated. Add remaining flour and mix to combine. Add the water and mix at medium speed until the dough comes together around the paddle into a firm mass.
Take the dough out of the bowl and divide it into two halves. Pat each half into a neat disk, wrap them snugly in plastic wrap, and refrigerate for at least 30 minutes. If you’ve got time, let it chill overnight for a dough that’s smooth, supple, and easy to work with. Use as needed for pie or tart crusts.
This buttery, flaky pastry is enough for two tarts or one pie with a top crust. If you’re only baking one tart today, just wrap the second disk in cling wrap and stash it in the freezer for your next baking adventure.