Add flour, icing sugar, and salt in a food processor and pulse a few times to combine.
Add the butter, and process until the butter is blended coarsely. Add in the egg yolk, and process in 10-second pulses, until the mixture is granular, and clumps begin to appear.
Dump the dough onto a work surface. Finish blending the dough with the heel of your palm. Form the dough into a disk, and place between two pieces of parchment or wax paper.
Roll the dough, making sure to turn the disk frequently to ensure it's even. The dough will be about 1/8 inch thick.
Refrigerate the dough for 2 hours, or freeze for 1 hour. When ready to bake, allow the dough to sit at room temperature for about 10 minutes, or until it's pliable and can be formed without breaking.
Remove the dough from the paper, and form into a buttered tart pan. Trim the excess, and prick the bottom with a fork and freeze for 30 minutes, or longer.
Preheat the oven to 400 degrees.
Lightly butter a piece of foil and form to fit ontop of the crust. Place pie weights, dried beans, or rice on the foil. Bake the crust for 25 minutes, then carefully remove the foils and weights, and bake for another 7-10 minutes. Cool completely.