1 cup (225 g) unsalted butter, at room temperature
½ cup (65 g) icing sugar, plus extra for dusting
2 Tbsp (30 mL) espresso coffee, cooled
2 tsp vanilla extract
2¼ cups (337 g) all-purpose flour
¼ cup (30 g) cocoa powder (regular or Dutch process)
¼ tsp fine salt
Granulated sugar, for coating
Directions
Preheat the oven to 325°F (160°C) and line two baking trays with parchment paper.
Beat the butter and icing sugar together by hand or using electric beaters on medium speed. Stir in the espresso and vanilla.
Sift in the all-purpose flour, cocoa powder and salt and mix until the dough comes together.
Lightly dust a work surface with icing sugar. Divide the dough into two pieces and shape them into logs about 12 inches (30 cm) long. Flatten each log with your hand, then use a sharp knife to cut each log on an angle into ½-inch (1.2 cm) slices. Stand the cookies upright on the baking trays, leaving at least an inch (2.5 cm) between them.
Bake the cookies for 20 minutes, until they lose their shine and can be lifted easily from the baking tray.
Place the granulated sugar in a wide shallow bowl. Gently toss the warm cookies, two at a time, in the sugar and transfer them to a wire rack to cool.
The shortbread will keep in an airtight container at room temperature for up to 5 days.
