Directions
<ol class="no-list-style"><li class="MethodStepper"><h4 class="step-title">Step 1</h4>Begin by creaming together the softened butter, tahini, granulated sugar, and brown sugar in the bowl of a stand mixer fitted with the paddle attachment (or use a hand mixer) on medium-high speed for about 3-4 minutes. This extended creaming creates air pockets for a lighter texture and helps dissolve the sugar crystals for a chewy interior. The mixture should become noticeably lighter in color and fluffy in texture.</li><li class="MethodStepper"><h4 class="step-title">Step 2</h4>Add the egg and egg yolk one at a time, beating well after each addition until fully incorporated. Then mix in the vanilla extract. The extra egg yolk adds richness and contributes to the cookies' chewy texture. Scrape down the sides of the bowl as needed to ensure even mixing.</li><li class="MethodStepper"><h4 class="step-title">Step 3</h4>In a separate bowl, whisk together the flour, baking soda, baking powder, and salt until well combined. The baking soda and powder work together to give the perfect rise while maintaining chewiness.</li><li class="MethodStepper"><h4 class="step-title">Step 4</h4>With the mixer on low speed, gradually add the dry ingredients to the wet ingredients until just combined. Be careful not to overmix, which can develop the gluten in the flour and result in tough cookies. You should stop mixing as soon as no dry flour is visible.</li><li class="MethodStepper"><h4 class="step-title">Step 5</h4>Gently fold in the chopped chocolate by hand using a rubber spatula. Using chopped chocolate instead of chips creates melty chocolate pockets of various sizes throughout the cookies, enhancing both texture and flavor. Reserve a small handful to press into the tops of the cookies before baking if desired.</li><li class="MethodStepper"><h4 class="step-title">Step 6</h4>Cover the dough with plastic wrap, pressing it directly onto the surface, and refrigerate for at least 2 hours or up to 24 hours. This resting period allows the flour to fully hydrate and the flavors to develop. The sesame notes from the tahini will become more pronounced with longer chilling.</li><li class="MethodStepper"><h4 class="step-title">Step 7</h4>When ready to bake, preheat your oven to 180°C (350°F) and line baking sheets with parchment paper. Let the dough sit at room temperature for 10 minutes to make it easier to scoop if it's very firm from refrigeration.</li><li class="MethodStepper"><h4 class="step-title">Step 8</h4>Use a cookie scoop or tablespoon to portion the dough into 45g balls (about 2 tablespoons), placing them at least 5cm apart on the prepared baking sheets. The cookies will spread during baking, so give them plenty of room.</li><li class="MethodStepper"><h4 class="step-title">Step 9</h4>If using, sprinkle each cookie with a few sesame seeds and a tiny pinch of flaky sea salt. Then press any reserved chocolate pieces into the tops. These finishing touches add visual appeal and enhance the tahini's nutty flavor.</li><li class="MethodStepper"><h4 class="step-title">Step 10</h4>Bake for 11-13 minutes until the edges are set and golden brown, but the centers still look slightly underbaked. This is the secret to chewy centers! The cookies will continue cooking slightly on the hot baking sheet.</li><li class="MethodStepper"><h4 class="step-title">Step 11</h4>Allow the cookies to cool on the baking sheets for 5 minutes before transferring to a wire rack to cool completely. The cookies will firm up during this time but maintain their chewy centers.</li><li class="MethodStepper"><h4 class="step-title">Step 12</h4>Store cooled cookies in an airtight container at room temperature for up to 5 days, though they're at their absolute best within the first 2 days. For longer storage, freeze the baked cookies for up to 3 months, or freeze the portioned dough to bake fresh cookies whenever the craving strikes!</li></ol>