Using a stand mixer with the paddle attachment put the flour, sugar, and salt in the bowl and mix at low speed to incorporate.
1 ¼ cups AP flour, ¼ cup Powdered sugar, ¼ teaspoon Salt
Cut the butter in cubes and then add to the bowl and beat on medium-low speed just until the texture resembles small peas. Do not overbeat. It is helpful to chill the butter cubes before mixing if it is a warm day.
8 tablespoons butter
In a small mixing bowl add the egg yolk, water, cream, and vanilla. Mix together then add to the mixing bowl and mix on low until the dough pulls away from the sides.
1 egg yolk, 1 tablespoon cream, 1 teaspoon vanilla, 1 tablespoon ice water
Place the dough on a lightly floured surface and roll into a 12" circle to fit the tart pan.
Roll the dough around the rolling pin and place it over the tart pan then unroll the dough and fit the pastry into the pan. Press the corners and edges of the dough to fit the pan, lifting the pastry as needed to fit into the pan.
Once the dough is in the tart pan there will be excess dough hanging over the sides of the pan. Take the rolling pin and roll it over the top of the tart pan to cut away the excess dough.
With the tines of a fork, press the tines into the dough to allow for venting.
Place the tart pan with the dough into the refrigerator and chill for 15 -30 minutes.