Always make sure you have prepared all tools and ingredients before you start mixing: line the baking tin with parchment paper, preheat the oven and get all the ingredients out ready to use. It is easy to get flustered if you feel unprepared!
This brownie mixture, if the butter cools a lot, is really quite a thick one. No need to be alarmed by this, the brownies will turn out wonderful once baked!
Toast the Kataifi pastry until it is a beautiful golden colour. Make sure the pan used is large enough, or alternatively cook it in two smaller batches. Making sure the pastry is dry and crispy will give you the perfect texture for the Dubai chocolate bar filling.
I would definitely recommend using a pistachio cream rather than a pistachio butter. A pistachio butter will contain more natural oils than a cream, giving the finished dessert more of an oily texture. I link to the one I used in the recommended table above.
When cutting the pistachio chocolate brownies, use a knife that is warm rather than hot. This will help it slide through the top chocolate layer more smoothly, reducing the chances of it cracking and breaking. Make sure to clean the knife between cuts too.