Line a baking sheet with parchment paper and set aside. Spread the arils in a loose layer on a double layer of paper towels. Cover and blot gently with another paper towel, rolling them around to contact dry parts of the toweling. Gather up the towels and transfer the arils to fresh dry towels. Spread, blot, and roll, as before. Repeat if necessary. Let the arils air dry for another 10 or 15 minutes (sometimes I fan them for a few seconds with a magazine).
Meanwhile spread the nuts on a chopping board and cut them into pieces not much bigger than the arils. Shake them in a coarse strainer to remove the dust—and reserve the dust for another use (morning cereal, another recipe, smoothie…).
Temper the chocolate (https://food52.com/blog/3601-how-to-temper-chocolate) or simply melt it as follows: Chop it coarsely and put it in a medium stainless steel bowl set directly in a wide skillet of almost simmering water. Stir frequently until it is almost entirely melted. Remove the bowl and stir until completely melted and smooth. It should be warm—between 110° and 120° F; let cool for a few minutes if it exceeds 120° F.
Wipe the bottom of the bowl dry prevent dripping. Save 1/3 of the arils and walnuts for topping, if desired. Otherwise, pour all on top of the chocolate. Using a rubber or Silicone spatula, gently fold the inclusions into the chocolate without bruising the arils and releasing juices: To do this, try to avoid direct contact between the spatula and the arils by sweeping the edges of the spatula down the side of the bowl, across the bottom under the chocolate and inclusions and up the opposite side of the bowl, lifting the chocolate up and over the nuts and arils. Repeat just until all of the inclusions are coated.
Immediately scrape the mixture onto the parchment over a wide area rather than one big heap—don’t worry about uneven distribution or bare spots. Then, instead of trying to spread the mixture out, use the tip of the spatula to gently push and distribute the coated inclusions to make the bark thinner and fill in some of the bare spots on the parchment. Sprinkle with reserved nuts and arils, if desired.
If chocolate is not tempered, put the baking sheet immediately into the fridge to set and harden the chocolate, then cover it with plastic wrap to prevent condensation and the absorption of odors and keep refrigerated. It will keep for 1 to 2 days with toppings; 3 days without. You can remove it 15 to 30 minutes in advance of serving.
If chocolate is tempered, leave the sheet in a cool place (I tape the corners of the parchment to the baking sheet and set it front of a small table fan) to set. Store at room temperature 1 to 2 days with toppings, 3 days without. (You can get 1 or 2 additional days of life from tempered bark with all arils coated as follows: At least 3 hours after the chocolate is set, wrap bark in plastic wrap and a ziplock bag and refrigerate. Bring to room temperature before unwrapping, gifting, or serving.)
To serve, break the bark into pieces/shards with your fingers or the point of a paring knife.
My career was sparked by a single bite of a chocolate truffle, made by my Paris landlady in 1972. I returned home to open this country’s first chocolate bakery and dessert shop, Cocolat, and I am often “blamed” for introducing chocolate truffles to America. Today I am the James Beard Foundation and IACP award-winning author of ten cookbooks, teach a chocolate dessert class on Craftsy.com, and work with some of the world’s best chocolate companies. In 2018, I won the IACP Award for Best Food-Focused Column (this one!).