Directions
<ol class="no-list-style"><li class="MethodStepper"><h4 class="step-title">Step 1</h4>First, prepare the pistachio filling. In a food processor, pulse the pistachios with the granulated sugar until finely ground but not pasty. Add the softened butter, cardamom, almond extract (if using), and salt, then process until the mixture forms a smooth, spreadable paste. The natural oils from both the pistachios and butter will help create this cohesive filling. Transfer to a small bowl and set aside at room temperature.</li><li class="MethodStepper"><h4 class="step-title">Step 2</h4>For the dough, combine the flour, granulated sugar, icing sugar, and salt in the food processor and pulse to mix. Add the cold cubed butter and pulse until the mixture resembles coarse breadcrumbs – this should take about 10-12 pulses. Using cold butter is crucial as it creates small pockets that will make your cookies tender and flaky.</li><li class="MethodStepper"><h4 class="step-title">Step 3</h4>Add the vanilla extract and egg yolk to the food processor. Pulse just until the dough starts to clump together and can be pressed into a ball. Be careful not to overmix, as this will develop gluten and make your cookies tough rather than tender. If the dough seems too dry, add 1-2 teaspoons of cold water.</li><li class="MethodStepper"><h4 class="step-title">Step 4</h4>Turn the dough out onto a lightly floured surface and gently bring it together with your hands. Divide the dough into two equal portions and form each into a rectangle. Wrap each portion in cling film and refrigerate for at least 30 minutes, or until firm enough to roll. Chilling allows the butter to solidify, preventing the dough from spreading too much during baking.</li><li class="MethodStepper"><h4 class="step-title">Step 5</h4>Working with one portion of dough at a time, roll it out between two sheets of parchment paper into a rectangle approximately 25cm × 20cm (10in × 8in) and about 5mm (1/4in) thick. Try to keep the edges as straight as possible for neat pinwheels.</li><li class="MethodStepper"><h4 class="step-title">Step 6</h4>Using an offset spatula, spread half of the pistachio filling evenly over the rolled-out dough, leaving a 1cm border along one of the long edges. The filling should be spreadable but not so soft that it oozes – if it's too firm, let it sit at room temperature for 5-10 minutes.</li><li class="MethodStepper"><h4 class="step-title">Step 7</h4>Starting from the long edge opposite the clean border, carefully roll the dough into a tight log, using the parchment paper to help you. The clean border will help seal the log. Once rolled, gently press along the seam to seal it completely. Repeat with the second portion of dough and remaining filling.</li><li class="MethodStepper"><h4 class="step-title">Step 8</h4>Brush each log lightly with beaten egg white, then roll in granulated sugar to coat the outside. The egg white helps the sugar adhere and creates a slightly crisp, sweet exterior. Wrap each log in parchment paper and refrigerate for at least 2 hours, or preferably overnight. This resting time allows the flavors to meld and the log to firm up, making it easier to slice cleanly.</li><li class="MethodStepper"><h4 class="step-title">Step 9</h4>When ready to bake, preheat your oven to 180°C (350°F) and line baking sheets with parchment paper or silicone mats. Remove the logs from the refrigerator and let them sit at room temperature for about 5 minutes to slightly soften (this prevents cracking when slicing).</li><li class="MethodStepper"><h4 class="step-title">Step 10</h4>Using a sharp knife, slice the logs into rounds about 1cm (just under 1/2in) thick. If the dough crumbles when cutting, let it warm up for another minute or two. Place the slices on the prepared baking sheets, spacing them about 5cm (2in) apart as they will spread slightly.</li><li class="MethodStepper"><h4 class="step-title">Step 11</h4>Bake for 11-13 minutes, or until the edges are just beginning to turn golden while the centers remain pale with a hint of the green pistachio showing through the swirls. Don't overbake – these cookies should be tender rather than crisp throughout.</li><li class="MethodStepper"><h4 class="step-title">Step 12</h4>Allow the cookies to cool on the baking sheets for 5 minutes (they'll be quite delicate while hot), then transfer to wire racks to cool completely. Once cooled, store in an airtight container at room temperature for up to 5 days, or freeze for up to 3 months. The unbaked logs can also be frozen for up to 2 months – just slice and bake directly from frozen, adding 1-2 minutes to the baking time.</li></ol>