01 - Line a 9x13 inch baking sheet with parchment paper and set aside.
02 - Toast the coconut flakes in a dry skillet over medium heat for 2–3 minutes, stirring frequently, until lightly golden. Remove from heat and let cool.
03 - Melt the dark chocolate in a heatproof bowl set over a pot of simmering water (double boiler method), or microwave in 20-second bursts, stirring between each interval, until completely smooth.
04 - If using, stir the maple syrup or honey into the melted chocolate until well incorporated.
05 - Reserve 2 tablespoons each of toasted coconut flakes and chopped cashews for the topping. Fold the remaining coconut and cashews into the melted chocolate.
06 - Pour the chocolate mixture onto the prepared baking sheet and spread into an even layer about 1/4 inch thick.
07 - Sprinkle the reserved coconut flakes, cashews, and flaky sea salt evenly over the surface of the bark.
08 - Refrigerate the bark for about 30 minutes, or until fully firm and set.
09 - Remove from the refrigerator and break into irregular pieces. Store in an airtight container at cool room temperature or in the refrigerator.