Preheat the oven to 350°F (180°C). Line two baking sheets with parchment paper.

In a large mixing bowl with a hand mixer, beat the softened butter, granulated sugar, and brown sugar until smooth and glossy.

Add the egg, egg yolk, and vanilla. Mix until fully combined.

In a separate bowl, whisk together the flour, cocoa powder, baking soda, and salt.

Add the dry ingredients to the wet mixture and fold gently with a spatula just until combined. The dough will be thick and soft.

Scoop 2½–3 tablespoons of dough per cookie and roll into balls. Flatten into a 1 inch tall disc. Place them 3 inches apart.

Bake for 11-13 minutes, until the edges are set but the centers still look soft.

While the cookies are still warm, gently press the centers down with the back of a spoon or glass to create a shallow well.

Let cool completely on the baking sheet.

In a skillet over medium heat, melt the butter. Add the chopped kataifi and cook, stirring frequently, until golden brown and crisp, about 5–7 minutes. Remove from heat and let cool slightly.

Mix the toasted kataifi with the pistachio cream, melted white chocolate, and chopped pistachios until evenly combined.

Spoon a generous layer of the filling onto the center of each cooled cookie.

Melt the semi-sweet chocolate chips with the coconut oil until smooth and glossy.

Spoon or spread a thin layer of chocolate over the pistachio filling, allowing it to drip toward the edges.

Melt the pistachio cream and white chocolate together, adding a little coconut oil as needed until pourable.

Drizzle over the chocolate layer using a spoon or piping bag. Top with chopped pistachios if desired.

Let the chocolate set at room temperature or refrigerate briefly until firm.