Add the white chocolate to a small, microwaveable bowl. Microwave in 30 second increments, stirring each time, until melted. Add in a drop of green food coloring. Drizzle a little into the bottom of each mold cavity to create a design.

Add the dark chocolate chips to another microwavable bowl and microwave in 30 second increments, stirring each time, until melted. Add a few teaspoons to the bottom of each mold and spread evenly with a spoon to coat the bottom and sides. Place in the fridge to harden.

Add the butter to a skillet over medium heat and melt. Once melted, add in the kataifi pastry and toss to coat evenly in the butter. Continue to let the pastry toast, stirring often. Once golden brown, transfer to a bowl.

Add the vanilla and pistachio butter to the kataifi mixture and toss to evenly combine.

Take the egg shells out of the fridge and fill each with some of the filling, leaving about 1/4-inch of room at the top. Top each with remaining melted dark chocolate to fill. Place back in the fridge to harden completely before removing from the molds and eating.