Preheat your oven to 180°C (350°F) and line your baking trays with parchment paper.

In a pan, melt a knob of butter and add the kataifi pastry. Toast it for about 10 minutes until golden brown and crunchy, then let it cool.

In a large mixing bowl, cream cold unsalted butter with light brown sugar, superfine sugar, and vanilla extract until fluffy. Add cold egg and mix briefly.

Sift in cake flour, baking powder, and salt. Fold in the dry ingredients until just combined, then add chocolate chips.

In another bowl, mix cooled toasted kataifi, pistachio paste, tahini, and salt until smooth.

Scoop out cookie dough, roll into balls, flatten slightly, add nutty filling in the center, and seal the dough back around it.

Bake for 20-22 minutes until edges are golden brown and centers are soft, then let them rest for 20 minutes before cooling completely on a wire rack.

Melt chopped chocolate and drizzle over cooled cookies. Sprinkle with toasted pistachios and leftover kataifi.