1. For the crust: Mix the melted butter and cookies together until combined. Pour the mixture into a loose-base pie pan (approx. 15 in diameter) and press firmly along the bottom and up the sides. Cover and refrigerate the crust for at least 1 hour.
2. For the filling: Melt the chocolate over a water bath and combine with the yogurt. Pour the filling into the crust – using a piping bag if you have one. Decorate with raspberries and sifted powdered sugar.
You can substitute dark or white chocolate for the milk chocolate.