Very Dark Chocolate and Pistachio Bark
Line a board with baking parchment and set aside. Very finely chop the Extra Dark Chocolate into small pieces and put approx. two thirds (65g (2 ½ oz)) into a clean and dry heatproof glass or plastic (not metal) bowl. Quarter fill a larger bowl with cold water and set aside.
Put the bowl of chocolate over a saucepan of barely simmering water to melt slowly – do not let the bottom of the bowl touch the water as you want the chocolate to melt gradually and not get too warm too quickly. Stir the chocolate occasionally using a plastic spoon or spatula, and once the chocolate is almost melted, put in a sweet making thermometer; alternatively, you may find it easier to use a clean food probe. It is important to keep stirring the chocolate every now and then so that the temperature is consistent throughout the melt.
Once the chocolate has melted to 42°C (108°F) – this should take around 3 minutes, immediately remove from the hot water and sit the bowl in the cold water for a few seconds to prevent the temperature rising any further. Note: if your chocolate does heat beyond the desired temperature, it will still be fine to use, it just won't be tempered and may look less shiny when set.
Remove from the water and wrap a tea towel round the bottom of the bowl to retain the heat. Add the remaining chopped chocolate and stir the chocolate for a few minutes until the pieces melt, then remove the tea towel and continue mixing the chocolate letting it cool to 31-32°C (88-90°F) – this process may take as much 10 minutes depending on the kitchen air temperature.
Once it has cooled to the correct temperature, the chocolate is ready to use. Scrape it out of the bowl using a plastic spatula on to the centre of the paper and carefully spread to form a rectangle approx. 12 x 15cm (5 x 6 inches). Then, working quickly, grind over Vanilla Grinder to taste and sprinkle with the chopped pistachios; put in a cool place to set.
Once the chocolate is firm, your chocolate is perfectly tempered and ready for packing and gifting.
Tempering chocolate before you use it will give you a professional finish to your chocolate work. The chocolate will be shiny, crisp and much more stable at room and chilled temperature. Extra Dark Chocolate is the easiest of chocolate varieties to temper, but if you do want to try others, Milk Chocolate needs to cool to 30-31°C (86-88°F) before use, and White to 27-28°C (80-82 °F).