Place parchment on a cookie sheet. Finely chop chocolate and place in bowl.
Set bowl with chocolate over a small saucepan with 1-inch simmering (not boiling) water and melt, stirring every so often until chocolate is melted and smooth. Set aside ¼ cup of chocolate.
Stir in freeze-dried raspberry powder and Hedessent flavourings. Pour chocolate onto parchment paper and spread out to form a sheet of chocolate ¼ to ⅛ inch thick.
Sprinkle on chopped pistachios while chocolate is still wet. Drizzle the remaining white chocolate over nuts in an abstract design. Chill in the refrigerator until hard.
Break into large shards and enjoy. This will keep in an airtight container for 2 months in the fridge.
Notes
Use good quality chocolate for best results. Bar chocolate is recommended, as chips do not melt as easily.Freeze-dried raspberries are available in some health food stores and on Amazon. Chocolate can also be melted in a microwave. Just remember to do so in short intervals, 20-30 seconds at a time, stirring in between until the chocolate is melted and smooth.