In a food processor (or a large bowl) whisk together flour, salt and sugar. Grate butter atop the mixture. Pulse 4-6 times (or use a pastry blender) until the mixture is crumbly.
Add 3 tablespoons cold water. Stir it into the mix and the dough should start forming clumps. If needed add water, tablespoon by tablespoon, until the dough sticks together. Lay a sheet of plastic wrap on your work surface, dump the dough onto it and knead it into a ball.
Flatten dough into a disk, wrap well and chill in the freezer for 30 minutes or in the refrigerator for 2 hours (can also do this overnight).
When ready, take dough out of the refrigerator. Let it rest at room temperature for 5 minutes. Generously flour your work surface and rolling pin. Roll out the dough to a 10-inch (26-cm) round, making sure you rotate it every so often, so it doesn’t stick as you’re rolling it out.
Wrap dough around the rolling pin and unroll it over the tart pan. Gently fit in the sides, trim any dough hanging over the pan. Pierce the bottom of the crust with a fork. Place in the refrigerator for 15 minutes.
Preheat oven to 425°F (215°C). Take the tart pan out of the freezer. Place a piece of parchment over it. Fill it up with baking beans. Bake for 15 minutes.
Remove tart from oven and lower temperature to 375°F (190°C). Remove the beans and parchment paper from the crust. Continue baking the crust for 10 minutes or until the pastry is golden brown. Remove from the oven and let it cool completely.