Classic Shortbread Cookies

Dump the flour in a large bowl, add the butter, and use your fingertips to rub them together until the mixture resembles fine breadcrumbs.

Stir in the sugar, vanilla extract, and salt, if using, and work the mixture with your hands until it forms small clumps. Continue kneading the cookie dough until it's smooth and the sides of the bowl are clean. It's okay if the cookie dough is a little crumbly. (You can wrap the dough in plastic wrap and refrigerate for up to several hours although you'll need to let it warm at room temperature before you're able to roll it.)

Gently roll out the dough between a couple sheets of parchment paper or plastic wrap to a thickness between 1/4 and 1/2 inch (1/2 to 1 1/4 centimeters). The dough is a little more crumbly and dry than most roll-out cookie doughs, so don't worry if it cracks or crumbles a little.

Carefully transfer the dough to the refrigerator or freezer for at least 15 minutes. (The time spent in the fridge may test your patience, but it helps set the dough so it doesn't spread into blobs during baking. If you're impatient and bake the dough without chilling, chances are you'll end up with some amorphous starfish rather than linear stars.)

Preheat the oven to 275°F (130°C). Line a baking sheet with parchment paper.

Using a star cutter, cut out the cookies and transfer them to the baking sheet. Roll the scraps and cut out as many more cookies as you can. It may be necessary to let the dough rest at room temperature for a little while prior to being able to roll it out.

Bake the cookies in the preheated oven for 22 to 30 minutes, until very pale gold in color.

Remove the cookies from the oven, let them cool a few minutes on the baking sheet, and then sprinkle with superfine sugar while still warm.