"Chocolate bark makes a beautiful edible holiday gift. When you melt chocolate for bark or dipping fruit, you need to temper it, usually using a thermometer. This new method I was told about seemed just too easy, so I had to try it. It worked out fairly well!"
Chop dark chocolate into small pieces. Separate into 2 portions 1/3 in 1 portion, 2/3 in the other. Place 2/3 of the chocolate into a heatproof bowl, preferably metal. It should be large enough to sit on the rim of a pot without touching the water.
Heat about 2 inches water in a pot over medium-high heat until it just barely starts to simmer. Reduce heat to lowest setting; place bowl over pot. Allow chocolate to melt without stirring until about 2/3 of the pieces have melted. Stir until all pieces have melted and chocolate feels hot (not boiling hot) to the touch (about 115 to 120 degrees F), about 2 minutes.
Transfer the remaining third of chocolate to the bowl. Stir until melted. Place bowl on the counter and, stirring occasionally, cool chocolate until it's cool to the touch and beginning to thicken up a bit, about 8 minutes. Chocolate should be smooth and shiny.
Line a rimmed baking sheet with a silicone mat (or parchment paper or waxed paper). Slowly pour the chocolate into the lined pan not all the way to the edges. Sprinkle the chopped walnuts, pistachios, and goji berries evenly over the chocolate. Top with a bit of coarse sea salt.
Allow to sit at room temperature to cool and harden. Break into pieces.