Add cold butter into the bowl of a stand mixer with a paddle attachment or use a hand held mixer. Beat on medium high speed for 1 minute.
½ cup cold unsalted butter
Add the egg and vanilla extract and mix on medium high speed for 30 seconds. It might look lumpy but that's okay.
1 large egg, 1 tsp vanilla extract
Add the powdered sugar and salt and beat on medium high speed until incorporated. Turn the mixer onto low speed, add the flour in two parts. Mix until the dough comes together and looks smooth.
½ cup powdered sugar, ¼ tsp kosher salt, 1 ½ cup all-purpose flour
Scrape the dough off the sides of the bowl with a rubber spatula. Lay out a piece of plastic wrap on a flat surface. Gently knead the dough into a ball using your hands, place it on the plastic wrap, and flatten into a disc. Refrigerate for at least 1 hour or overnight. If you skip this step, the tart crust will melt in the oven.
Preparing The Tart Crust
Spray a 9 or 10-inch tart pan with a removable bottom with nonstick cooking spray.
Lightly flour a clean surface and roll out the dough with a rolling pin. It might be a little hard at first because the dough is could, but keep rolling. After each roll, turn the dough a quarter turn with your hands so that it will be an even thickness.
Roll out to about 1/8-inch thick. Carefully pick up the dough and lay it over the tart pan. Use your fingers to push the dough into the sides of the pan.
Use a sharp knife to trim any dough that hangs over the edges of the pan. If the dough has any cracks, patch it with the excess dough. Place in the freezer for 30 minutes.
Preheat the oven to 350℉ (177℃). Bake the tart crust on the center rack for 25-28 minutes, turning halfway. Look for a golden brown crust and the edges start to slightly pull away from the pan. If the edges start getting too dark, cover with tinfoil.
Remove from the oven and let cool for 30 minutes. To remove from the tart pan, push the removable bottom up from underneath.
This crust can be left at room temperature for 2 days, wrapped in tinfoil or an airtight container.