Step 1: Melt the butter in a large skillet over medium heat. Add the finely chopped kunafa pastry and stir continuously for 5-8 minutes until golden brown and very crunchy. Remove from heat and transfer to a bowl to cool.
Step 2: In a medium bowl, combine the cooled toasted kunafa, pistachio cream, tahini, and sea salt. Mix until the pastry is evenly coated and the mixture forms a thick paste.
Step 3: Temper the chocolate: Melt 2/3 of the chocolate in a double boiler to 115°F. Remove from heat, add the remaining 1/3, and stir until the temperature drops to 88-90°F.
Step 4: Pour a thin layer of chocolate into the bottom and sides of your silicone chocolate molds. Tap the mold on the counter to remove air bubbles. Invert the mold over parchment to remove excess, then refrigerate for 10 minutes to set.
Step 5: Fill the chocolate shells with the pistachio-kunafa mixture, leaving about 2mm of space at the top. Press down gently to ensure there are no air pockets.
Step 6: Pour the remaining tempered chocolate over the filling to seal the bars. Use a bench scraper or offset spatula to level the top and remove excess chocolate. Refrigerate for at least 30-60 minutes until completely firm.