Step 1: Finely chop the kunafa pastry into small shreds using a knife or food processor.
Step 2: Melt the butter in a large skillet over medium heat and add the shredded kunafa, stirring constantly until it becomes a deep golden brown and very crispy.
Step 3: Transfer the toasted pastry to a bowl and let it cool slightly before mixing in the pistachio butter and tahini until fully combined.
Step 4: Melt two-thirds of your chocolate in a microwave-safe bowl or double boiler, then stir in the remaining third to temper it for a glossy finish.
Step 5: Pour a thin layer of chocolate into your bar molds, making sure to coat the sides, then chill in the fridge for 5-10 minutes until set.
Step 6: Spoon the pistachio kunafa mixture into the chocolate shells, pressing down gently to ensure it is level, leaving a small gap at the top.
Step 7: Pour the remaining melted chocolate over the filling to seal the bars, scraping off any excess with a spatula, and refrigerate for at least 1 hour before unmolding.