In a microwave-safe bowl, microwave the white chocolate for 20 seconds or until meted. Drizzle it with a fork in the chocolate molds, and then freeze for 15 minutes.
In another microwave-safe bowl, add the chopped milk chocolate and microwave for 20 second intervals until melted and smooth.
Pour half the melted chocolate into the mould over the white chocolate (it must cover the bottom of the mould) and freeze for 20-30 minutes until solid.
Now, in a large frying pan, melt the butter over medium-high heat and stir the kataifi in constantly for about 10 minutes until browned.
Take the pan off the heat and, stir in the pistachio butter and tahini, and then let it cool completely.
Spread the pistachio filling mixture equally over the chocolate in the mold.
Pour the remaining melted chocolate evenly over the pistachio filling to cover it. Freeze for 25 minutes more. Once solid Remove from molds, cut and enjoy.
Notes
Store it in the refrigerator to hold its shape and stay crunchy.