Get out a standard 9” (23cm) pie plate. It should be one that's safe to move from the fridge to a hot oven (see post for more info). Do not grease it.
To the bowl of a food processor fitted with an S-blade, add the flour, granulated sugar and salt. Pulse a few times.
1 1/4 cups (156 grams) flour, 1 tablespoon granulated sugar, 1/2 teaspoon fine sea salt
Turn it to the lowest speed and add in the butter. Process just until you have pea-sized bits of butter. Don’t overprocess! Stop pulsing.
1/2 cup (113 grams) unsalted butter
Evenly drizzle the vanilla extract and apple cider vinegar over the top.
1 teaspoon cold vanilla extract, 1/2 teaspoon cold apple cider vinegar
Turn on the lowest speed and pour in 2.5 tablespoons of water. The amount of water you need will depend on how cold your ingredients, kitchen, etc. are. I’ve made this several times with the same brand of ingredients, and have needed between 2.5 and 5.5 tablespoons.
2.5 to 5.5 tablespoons (37 to 81 grams) cold water
Process very briefly until it looks like it’s coming together. It’ll look shaggy and not like a uniform ball. Pinch some together. If it stays together without being crumbly, it’s ready. You don't want to add too much water. More water than necessary = non-flaky pie crust. If you think it needs a bit more water (it almost certainly will), add more water, 1 teaspoon at a time. If you think you can form a disc with it without it falling completely apart into a thousand crumbs, that’s another clue it’s ready.
Place the dough in the center of a large piece of plastic wrap and wrap it up into a flat disc, about 1” (2.5cm) or a little less. If you can’t form a disc because it’s nothing but crumbs, it needs a little more water.
Refrigerate for at least 45 minutes and up to 2 days.
Place a baking sheet on the baking rack (one in the lower third of the oven) that will fit your pie. This is for the very unlikely case that something spills over and for a crisper crust bottom. Preheat the oven to 350 °F (175 °C).
Very lightly flour a piece of parchment paper and place the unwrapped dough on there. Sprinkle a tiny bit of flour over the top of the dough.
Place the plastic wrap or another piece of parchment paper on top of the dough and roll it out so that it’s about 1/2” (1 1/4 cm) wider than the top circumference of your pie plate.
Remove the piece of plastic wrap or parchment covering the pie crust, place the ungreased pie pan on top of the dough, and then flip over the dough and pan. Press the dough down around the edges at the bottom of the pan and then remove the piece of parchment paper.
Fold the dough up so it's not hanging off the sides, and crimp the edges. The dough should go all the way up the edges and be crimped along the rim.
Place in the fridge, uncovered, for at least 15 minutes while preparing the filling.