Prepare the Kataifi Pastry: Preheat your oven to 350°F (175°C). Spread the kataifi pastry on a baking sheet and drizzle with melted butter. Toss to ensure even coating. Bake for 15-20 minutes, stirring occasionally, until golden brown and crispy. Let it cool completely.

Make the Pistachio Filling: In a bowl, combine the pistachio paste, tahini, and a pinch of salt. Mix until smooth. Once the kataifi has cooled, fold it into the pistachio mixture, ensuring even distribution.

Mold the Chocolate Shells: Melt 250g of the milk chocolate over a double boiler or in the microwave, stirring until smooth. Pour a thin layer of melted chocolate into silicone chocolate molds, ensuring the sides are well-coated. Tap the molds gently to remove air bubbles. Refrigerate for about 10 minutes to set.

Fill the Molds: Once the chocolate shells have set, spoon the pistachio-kataifi mixture into each mold, leaving a small gap at the top for the final chocolate layer. Press gently to ensure there are no air pockets.

Seal the Bars: Melt the remaining 250g of milk chocolate and pour over the filled molds, ensuring the filling is completely covered. Tap the molds again to remove air bubbles. Refrigerate for at least 30 minutes, or until fully set.

Decorate (Optional): Melt the pink and green chocolate melts separately, each with ½ teaspoon of coconut oil, until smooth. Drizzle over the set chocolate bars for a decorative touch.