In a mixing bowl, whisk together the flour, sugar, and salt.

Cut the softened butter into the dry mixture using a pastry cutter or fork until it resembles coarse crumbs.

Add the egg yolk to the mixture and stir until just combined.

Turn the dough out onto a lightly floured surface and knead gently.

Wrap the formed dough in plastic wrap and refrigerate for at least 30 minutes.

Roll the dough out on a floured surface to about 1/8 inch thick.

Carefully place the rolled dough into your tart pan, pressing it into the edges.

Preheat your oven to 350°F (175°C) and bake the crust for 20 minutes or until lightly golden.