Make the custard:

• Fill a deep and sturdy enough pot, or suitable sous vide container, with water and set your circulator to 80ºC/176ºF. Allow the jars to warm along with the water (see tip in post above). While the water heats, scale all your ingredients.
• Place the chocolate in a tall, heat-proof container, like a measuring cup and set aside. Heat the cream to a simmer, remove from the heat, add the coffee beans, cover and allow to infuse for about 15 minutes. Alternatively, you may infuse the cream with the beans in the refrigerator overnight, then heat as above. Strain out the beans and while still warm, pour over the chocolate and stir to melt (the cream may require a slight reheating before adding to chocolate to ensure the chocolate melts.
• Add the sugar, vanilla, salt and combine well. Add the yolks and use an immersion blender, or other blender to combine well. A whisk will work, if you don't have a blender.
• The water bath should be at temperature, so remove the jars and place on a towel (see tip in post above) - the water will be hot, so use tongs to prevent burning your hands. Remove the lids and pour in the contents slow and low to prevent air bubbles. Fill to just below the neck/threads. Remove any air bubbles with a torch, or tap the jars firmly on the towel. Seal with the lids, finger tip tight, and carefully place in the water bath to cook for 1 hour.
• When ready, remove jars from water bath with tongs and place on a towel, so they don't crack or shatter if your counter is too cool. Allow to cool at room temperature, then chill in the refrigerator for a few hours.
• Add a dollop of freshly whipped cream and a sprinkle of crisp pearls for texture contract. Enjoy!