Preparation

• Line two large rimmed baking sheets with parchment, and tape the parchment to the baking sheets. Put a piece of parchment on the counter, too. Have ready an instant-read thermometer.
• Mix the nuts, cinnamon, and salt in a small bowl. Transfer to a fine-mesh strainer and sift out the excess cinnamon and salt; reserve for another use.

Melt and temper the chocolate

• Finely chop 2 lb. of the chocolate and put it in a heatproof bowl that fits snugly over a 4-quart saucepan. Cut the other 1 lb. of chocolate into two pieces.
• 填满锅的水(约2英寸should not touch the bowl). Bring the water to a boil, remove the pot from the heat, and put the bowl of chocolate over it. Gently stir the chocolate occasionally with a silicone spatula until it is fully melted and reaches between 115°F and 120°F on an instant-read thermometer, 10 to 12 minutes.
• Remove the bowl from the pot, wipe the bottom dry, and add one of the 1/2 lb. blocks of chocolate to the bowl. Constantly fold the solid chocolate with the melted chocolate; the solid chocolate will melt somewhat but not fully. Take the temperature of the chocolate now and then. When it drops to 95°F, after 4 to 5 minutes, take what’s left of the solid chocolate out of the bowl. Add the second block of chocolate and fold constantly. When the temperature drops to 89°F, take the block out. (The chocolate blocks can be reused for other recipes.) Gently stir the melted chocolate for 1 minute more.

Spread the chocolate, top, and cool

• Divide the melted chocolate between the prepared baking sheets, and working quickly, spread it to about 1/4 inch thick with an offset spatula. Immediately sprinkle he nuts and cranberries over both sheets of warm chocolate, pressing down lightly.
• Place in a cool (60°F to 65°F) room or refrigerate it for just 5 minutes to set. For best results, let the bark sit for 12 hours before breaking it into shards.