Melt the butter in a large frying pan over medium heat, then add the katafi and cook until it is a lovely golden toasted color. On medium heat with occasional stirring, this should take about 10 minutes.
In a large bowl, stir together the pistachio cream, tahini and salt until combined.
Add the toasted katafi to the pistachio cream mixture and stir together until evenly distributed. Set aside while you prepare the chocolate.
Melt your chocolate over a double boiler, or in the microwave in 30-second bursts. For the absolute best results, temper your chocolate. It's a lot easier than you think! I have a post all about it, and you don't even need a thermometer.
Pour most of the melted chocolate into your molds and tilt it in every direction so the chocolate covers all sides of the mold. Then, tip the mold upside down over the chocolate bowl and shake it gently to remove all the excess chocolate. Put it in the fridge to set. If the chocolate is tempered, this should only take a minute or two, but it will take longer if it is not.
Once the chocolate has set, fill the molds with the crunchy pistachio filling and push it into all the corners. Be careful not to overfill or you won't be able to have a nice flat bottom on the chocolate bar.
Pour the remaining chocolate over the top of the bars to seal it in then use a bench scraper or spatula to run over the top of the mold and remove excess chocolate so you have nice clean edges. If the chocolate has cooled down too much, you can reheat it very gently, but be careful not to let it get too hot, or you might undo the tempering.
Put the chocolate bars in the fridge to set completely before turning them out of the molds.
Notes
Ingredient Notes:
Pistachio Cream - Make sure you use pistachio cream and NOT pistachio paste or pistachio butter. There are a lot of recipes out there that think these are interchangeable, but they are completely different things. Pistachio paste/butter is 100% pistachios blended up like any other nut butter, but pistachio cream is a sweetened, creamy spread that adds the sweetness to the dubai chocolate filling. Don't get them confused. Kataifi - This is phyllo pastry that has been shredded into very fine strands. You can find it online. I find it easiest to buy the kind that has already been dried and chopped. Chocolate - Make sure you use real chocolate, not chocolate chips or chocolate candy bars - these contain additives that stop them from melting properly, and you won't get the desired result. Go for a high-quality milk or dark chocolate.
Chocolate Tempering:
For the best results, I highly recommend tempering your chocolate. It's not strictly necessary, but will give your finished bars shine and snap, with a much more professional finish. It's a lot easier than you think - I have a post all about how to easily temper chocolate without a thermometer.