Line a baking sheet with parchment paper.

Melt the chocolate in a microwave-safe bowl in 30-second intervals in a microwave oven, stirring between each interval. Stop microwaving once 80% of the chocolate is melted. Stir until all of the chocolate is melted. My microwave oven melted the dark chocolate in 2:30 minutes.

Stir half the chopped pistachios (1 cup) into the melted dark chocolate.

Pour melted dark chocolate with pistachios on parchment-lined baking sheet and spread into an even layer about ⅛" thick, shaping sides into a rectangle if you can. Scatter remaining 1 cup of pistachios evenly over the chocolate. Sprinkle with flaky sea salt. Let chocolate cool completely, then break or cut into pieces.

Pistachio Sea Salted Dark Chocolate Bark will keep for about a week stored in a cool place in an airtight container between layers of parchment. Do not refrigerate.