Cut the butter in small pieces, then add to the bowl of a mixer with the powdered sugar. Cream the butter and sugar on speed 2 (kitchen-aid) for about 2 minutes.
In a small bowl, mix the egg and salt together. Once the butter has lightened in color, add the egg mixture.
Mix on speed 3 or 4 until you have a homogeneous mixture.
Add the flour, all at once, then mix on low speed, until just combined. If you mix too long, you'll start to develop the gluten in the dough which will make the tart shell shrink during baking. If the dough is too dry, feel free to add a tad bit of water.
Dump the dough out onto a lightly floured work space. With the palm of your hand, push the dough away from you and against the countertop. Do not overdo it, you should only need to repeat this action a couple of times to have a nicely combined dough.
Pull the dough together into a ball and then flatten into a disk. Wrap in plastic wrap and let rest in the fridge for 30 minutes.
Meanwhile, prepare a baking sheet with a sheet of parchment paper, then lightly butter and flour your tart ring or pan. Set aside.
At the end of the 30 minute resting period, roll out your tart dough until it's 3-4mm thick. Trim into a circle, leaving an excess of about two finger width around your tart ring. Using your rolling pin, transfer the dough onto the tart ring and start to work the dough into the corners. Using your thumbs, press the dough lightly against the tart ring. You're looking for a right angle around the entire circumference of the tart ring. This keeps the dough from shrinking during baking as there is no where for the dough to sag into.
Trim the excess dough from the top lip of the tart ring and prick the bottom of the tart shell with a fork. Let rest in the freezer for a minimum of 15 minutes.
Preheat the oven to 180°C (355°F)
Blind bake the tart shell for about 20-30 minutes. I generally start with about 20 minutes then check on the crust and adjust accordingly.
If you wish to use baking weights, line the tart crust with a sheet of parchment paper and add them prior to baking, however this is not necessary.
Let the tart shell cool on a baking rack (leave the tart ring on until cooled). Once the shell has cooled completely, you can use a micro-blader to clean up the sides and edges if there are any irregularities in the dough.