Place the chopped chocolate in a deep, wide bowl. Bring the heavy cream to a simmer, then pour it over the chocolate. Cover the bowl and let sit for 3-5 minutes.

Using a spatula, gently stir the chocolate into the cream until you have a smooth ganache. Place in the fridge and allow the ganache to set for about 90 minutes.

Using a small cookie scoop, scoop 18 balls of ganache over a baking tray lined with parchment paper. Refrigerate while you prepare the cookie dough.

Line 2 large baking sheets with parchment paper, and preheat the oven to 350°F (180°C).

Mix the flour, sugar, baking soda, and salt in a large bowl.

Add the butter and tahini, and use your hands to mix it all until you have a cohesive cookie dough.

Remove the ganache balls from the refrigerator. Use a medium-sized cookie scoop (holds 1 ½ tablespoons) to scoop the dough, then release the dough into your hand.

Press a ganache ball into the center of each cookie dough, then roll it with your hands and seal the cookie dough.

Press the dough to ½-inch thick rounds and place on the prepared sheet. Continue with the remaining dough and ensure 3 inches of space between each cookie.

Bake for 15-18 minutes until the edges are golden and the center does not appear raw. Remove from the oven and immediately use a large cookie cutter to swirl the cookies and give them a symmetric appearance.

Allow the cookies to cool before serving. Store the cookies at room temperature. If stored in an airtight container, they might get soft, so consider that.