Whisk together the yolk, cream and vanilla in a small bowl.
Place the flour, sugar and salt in a food processor and process briefly to combine. Add the cold butter pieces and pulse to cut the butter in until the mixture resembles coarse meal with pea-sized lumps, about 8 brief pulses.
With the processor still running, add the liquid egg mixture and process until the dough just comes together around the blade.
Turn the dough onto a sheet of plastic wrap and press into a 6-inch disk. Wrap the dough in the plastic and refrigerate at least 1 hour or up to 3 days.
Remove the dough from the fridge and let sit for 5 to 10 minutes to soften slightly. Roll out on a lightly floured surface until crust is slightly larger than your tart pan, about a 14-inch round. (If too sticky, try rolling between two lightly floured large sheets of parchment or plastic wrap.)
Carefully transfer the dough to a 10- or 11-inch tart pan. (It helps to use the rolling pin for this.) Ease the dough into the pan corners and press the dough against the fluted sides of the pan. Run the rolling pin over the top of the tart pan to remove the excess dough. Patch any thin spots or tears with the excess dough and trim away the edge again, if necessary.
Gently pierce the bottom of the crust with the tines of a fork. Freeze the tart crust in the pan for 30 minutes.
When ready to partially bake the crust, preheat oven to 375°F. Set the dough-lined tart pan on a baking sheet, then line the crust (bottom and sides) with foil or parchment. Fill with pie weights (rice, beans, ceramic, whatever you use) and bake for 15 to 20 minutes, or until foil or parchment doesn't stick to crust. Remove partially-baked shell from the oven, remove foil and pie weights and brush crust with egg white. Bake for another 5 minutes.