Line your baking pan with parchment paper to prevent the chocolate from sticking.
Place 2/3 of your white chocolate in a microwave safe bowl and then heat for 30. Then stir the chocolate thoroughly.
Repeat this step heating the chocolate and stirring the chocolate until the white chocolate is completely melted. Don't heat it past this point.
Now add small amounts of of your dry chocolate to the liquid white chocolate and stir it until in completely melts.
Continue this process adding small amounts of dry chocolate to the liquid chocolate until no more will melt.
Then pour your chocolate into the baking pan. Use a icing spatula to whip and stylize the surface and evenly spread the chocolate into all 4 corners.
Working quickly, while the chocolate is still liquid, add your sea salt sprinkling it evenly across the entire surface.
Next, evenly space your flower petals, pressing them gently into the surface of the chocolate.
Last, add your toasted pistachios. (To toast them, heat them ahead of time at 375°F for around 10 minutes in a baking sheet. Remove the pistachios when they are golden brown and rough chop them.)
Once all your ingredients are added, let your white chocolate bark rest for 1-2 hours.
Then, remove the chocolate from the baking dish and chop into 9 equal pieces with a heavy knife.
Serve!