ARCHIVE: Breton Shortbread Cookies or Tart Crust (from The French Market Cookbook)

• 1/2 cup/70g unrefined blond sugar (also sold as evaporated cane juice) or caster sugar
• 6 tbsp/85g high quality unsalted butter, softened
• 1 small fresh vanilla bean or 2 tsp pure vanilla extract
• 1 large organic egg
• 1 cup/130g all purpose flour
• 1 tsp baking powder
• 1/2 tsp fine sea salt

1. In the bowl of a stand mixer fitted with the paddle attachment, combine the sugar and butter. (Alternatively, do this by hand in a bowl with a wooden spoon.) Split the vanilla bean lengthwise with a sharp knife, scrape the seeds from the inside of the bean with the dull side of the blade, and add them to the sugar and butter. Beat the sugar and butter at low speed until pale an fluffy, about 3 minutes. Add the egg and beat for 2 minutes.
2. In another bowl, combine the flour, baking powder and salt, stirring with a whisk to remove any lumps. add to the mixer and mix at low speed for a few seconds, just until no trace of flour remains. The dough will be quite soft.
3. Transfer the dough to a container and refrigerate for at least 2 hours, and preferably overnight.
4. Preheat the oven to 350F/175C and line a baking sheet with parchment paper or a silicone baking mat.
5. Remove the dough from the fridge and roll it out between two sheets of parchment paper to a thickness of 1/3 in / 8mm. Peel off the top sheet gently and use a round cookie cutter, about 2 in /5cm in diameter, to cut out circles of dough.
6. Transfer to the prepared baking sheet, giving them a little room to expand.
7. Gather the scraps of dough and repeat to cut out more cookies. As the dough warms to room temperature, it may become to soft to work with; place it in the freezer for 10 minutes to firm up before cutting out circles again.
8. Bake the sables until golden brown, 15-20 minutes.
9. Transfer to a rack to cool completely. The sables will keep for a few days in an airtight container at room temperature.