To achieve the lightest, flakiest pastry possible, everything should be cold: the butter, the water, even the flour and the bowl you make it in.
2 1/2 cups all-purpose flour
3/4 teaspoon kosher salt
Optional: 1 Tablespoon sugar (see notes)
2 sticks cold, unsalted butter (16 Tablespoons total)
3/4 cup ice water (or a splash more or less as needed)
1. Use the scoop and level method (see this page) to measure the flour and salt into the bowl of a food processor with a metal blade, or a large bowl. Add the sugar if using, and mix to combine.
2. Cut the butter into small pieces and add them to the dry ingredients. Using either a food processor, a pastry cutter or your fingers, break up the butter into smaller and smaller pieces evenly distributed throughout the flour mixture.
If using a food processor, use the pulse button to pulse about 10-12 times to cut the butter into the flour mixture.
If using a pastry cutter, use a vertical circular motion to repeatedly move the blades of the cutter down, through and back up out of the mixture.
If using your fingers, use the tips of your fingers to repeatedly lift small portions of flour and butter up from the bowl, rub it between your thumb and fingers and let it drop back into the bowl.
Whatever method you use, the result should be that the butter is well integrated into the mixture, with very small pieces of butter, about pea-sized, still visible.
If using a food processor, dump the flour/butter mixture into a large bowl before proceeding.
3. Form a well in the middle of the flour/butter mixture and pour a few drops of ice water into the well. Use a rubber spatula to lift portions of the flour/butter mixture from the edges and drop it onto the wet portions. Keep adding water gradually as you continue to gently combine the dry portions of the flour/butter mixture with the wet portions,just until the mixture comes together enough to form a mass when pressed together. For a light, flaky crust, do not add too much water.
4. When the dough can be pressed together, split it into roughly equal halves and transfer them each into Ziplock-type bags. Press down on the dough in each bag to form a disk (this will make it easier to roll out).
5. Rest the dough in the refrigerator for at least 30 minutes, or up to 3 days, before rolling it out (a longer rest will make it easier to work with). Dough can also be frozen for a few months.
How Much Water? Adding the water to pate brisee is one of those things in cooking that requires your good judgment, rather than just following the recipe with precision. Many factors can affect the way the dough absorbs water on any given day, including the way the flour has been stored, the temperature and humidity in your kitchen, the particular brand of flour you are using and even whether the wheat was grown in the north or the south!
The bottom line: use only as much water as you need for the dough to form a mass when pressed together. Too much water will result in a tough crust, too little will make it impossible to roll out. Use your best judgment, learn as you go, and you'll be fine.
To sugar or not to sugar? Sugar can help to make your pie crust a tad more tender, but 99% of the time, I leave it out, and my pie crusts are as tender as can be. While sugar does change the chemistry of the mixture and help with tenderness, I find that handling the dough lightly and keeping it cold have at least as much effect, without the downsides (read on).
So why don't I use sugar? Two reasons.
First: taste. When I add sugar to the dough, I taste a hint of sweetness in the crust if I'm making something savory (like a quiche), and to me, it tastes out of place. However, when I'm making something sweet (like apple pie), the tiny bit of sugar in the crust is undetectable compared to the sweetness of the filling. So - sugar in the crust doesn't help the flavor, and may hurt it.
Second: convenience. If I leave the sugar out, the dough is an all-purpose workhorse, at the ready for whatever may come. I try to make it ahead (when I'm organized), and store it in the freezer so I can take it out when I'm ready to bake. This way, I keep my options open, and can use it for anything.