1 tsp. unsalted butter with 82% butterfat
Scant 1 1/2 cups (6 oz.) cocoa nibs
1/2 cup granulated cane sugar
1 1/2 cups (l4 oz. by weight) tempered white chocolate
Caramelize the nibs
Put a piece of parchment paper or a nonstick baking liner on a work surface. Measure the butter and put it next to the stove.
Put the nibs and sugar in a medium heavy-bottomed pot. Use an unlined copper pot if you have one. Place the pot over high heat and vigorously stir the mixture with a wooden spoon. As the sugar cooks, the mixture will smoke. When only a few specks of sugar remain unmelted, remove from the heat and stir in the butter. The nibs will glisten and separate into small clumps.
Scrape the nibs onto the parchment paper or baking liner and spread out the individual clumps. Let cool to room temperature and then break into 1/4-inch pieces. Store them in a zippered plastic bag at room temperature.
You will need 1 cup (4 oz.) caramelized nibs for the bark. Reserve the remaining caramelized nibs for other uses.
Make the bark
Line the bottom of an 8-by-12-inch sheet pan with parchment paper. Pour the chocolate into the prepared pan. Spread it evenly with a small offset spatula. Tap the pan on a work surface to even the top.
Sprinkle the caramelized nibs over the chocolate. When the chocolate loses its sheen and starts to set, after about 15 minutes, cut the bark with a sharp knife into 2-inch squares or other fanciful shapes of your choice. Leave the bark at room temperature until it is completely set, about t hour, and then separate the pieces.
Store in a cool, dry place, not in the refrigerator.