Melt 2 tablespoons of the unsalted butter in a large nonstick skillet over medium heat. Add 5 ounces coarsely chopped kataifi pastry dough. Cook, stirring occasionally, until golden-brown and crispy, 8 to 10 minutes. Transfer to a medium bowl.

Immediately stir in 1 (7- to 8-ounce) jar creamy pistachio butter, 2 tablespoons tahini, and 1/4 teaspoon kosher salt until evenly combined.

Place 2 large or 1 extra-large rectangular silicone Dubai chocolate mold(s) on a baking sheet.

Fill a small saucepan halfway with water and bring to a simmer over medium heat. Set a heatproof medium bowl over the simmering water to create a double boiler and add 3 tablespoons white chocolate chips. Cook, stirring constantly, until completely melted, about 1 minute.

Carefully remove the bowl from the double boiler. Stir in 1 to 4 drops green food coloring if using. Drizzle over the bottom of the chocolate mold(s) to create an irregular pattern. Freeze the molds while you melt the milk chocolate.

Set aside 1/4 cup milk chocolate chips from 12 ounces. Add more water to the saucepan if needed, then set the same bowl back over the water (no need to clean). Add the remaining milk chocolate chips and remaining 1 tablespoon unsalted butter to the bowl. Heat, stirring constantly, until completely melted, about 2 minutes.

Remove from the heat and stir in the reserved 1/4 cup milk chocolate chips until completely melted. Spread just enough of the melted chocolate (about 1/4 cup) to coat the bottom and sides of the mold(s) in a thin, even layer. Freeze the mold(s) until set, about 10 minutes.

Add the pistachio cream mixture to the chocolate mold(s) and use an offset spatula or the back of a spoon to gently spread and press the filling into an even layer. Pour the remaining melted chocolate over the top and spread into an even layer to fill the mold. Using a bench scraper or offset spatula, lightly scrape over the top to level and remove excess chocolate (you may have chocolate left over depending on the depth of your mold).