Cut butter in half lengthwise, turn it on the side, and cut it half lengthwise again. Then slice down the length of the stick of butter into 1/2 inch cubes. Put the butter back in the refrigerator.
Mix egg yolk, cream, and vanilla extract in a small bowl. Put in refrigerator.
Combine the flour, sugar, and salt in the bowl of a food processor.
Add the cold butter all at once to the flour and pulse until the texture resembles coarse cornmeal. There may be a few larger pieces, but no bigger than pea-sized.
Add the egg yolk mixture and pulse a few more times until the dough just starts to pull together.
Transfer the dough to a lightly floured work surface and gather it together. If your tart pan is round, gather the dough into a ball and flatten it into a disk. If you have a rectangular tart pan, gather it into a log and flatten it to a rectangle. Handle the dough as little as possible.
Wrap the dough in cling film or plastic wrap and refrigerate for at least 30 minutes, preferably an hour. If need be, you can freeze the dough for up to 3 months, well-wrapped.
To roll out, place the dough on lightly floured parchment paper. Lightly flour the surface of the dough as necessary. Roll out from the center of the dough, turning a quarter after each roll.
Roll the dough into either a disc or a rectangle, 2" wider than your pan.
Slide the dough parchment paper with the dough onto a cookie sheet and place the cookie sheet in the refrigerator for 20 minutes. This makes it easier to get it into your pan.
Spray tart pan with oil or release spray or butter it.
After 20 minutes, remove the dough from the refrigerator and lay it over the pan. Gently tuck the dough into the pan without stretching or pulling it.
Roll your rolling pin over the top of the pan to cut off the excess. Gently push the dough into each fold and bend of the tart pan. Save the excess dough to patch any cracks that appear during baking.
Cut a rectangle from a piece of aluminum foil slightly smaller than the inside of the tart pan and set the aluminum foil aside.
Prick the inside of the tart multiple times with a fork.
Place the tart in the freezer for 10-15 minutes.
Spray one side of the aluminum foil with oil or release spray.
Remove the tart from the freezer and place the aluminum foil over it. Bend the inside edges down over the edges of the tart pan. This will keep the edges from getting too brown.
Place a parchment paper over the tart shell and fill it with pie weights, beans, or rice. This will keep the dough from shrinking or bubbling up.
Place the tart back in the freezer for another 10-15 minutes. And preheat the oven to 375°F.
Bake the tart for 20 minutes. Take it out and carefully remove the aluminum foil and the parchment paper with your weights. Return to the oven for another 10-15 minutes, until dry and golden brown.
Remove the oven and let cool on the wire rack. Please DO NOT remove the tart from the pan until you are ready to serve it!
At this point, you can wrap the baked tart carefully and store it in the refrigerator.