Boil the cream, invert sugar, and salt together. Pour a third at a time over the 34 g Guittard Onyx 72% Dark Couverture Chocolate Wafers and 6 g Guittard Organic 38% Milk Couverture Chocolate Wafers and mix until emulsified.
Add 7 g Prova Gourmet Fusion Brazilian Coffee Flavored Cocoa Butter and mix with a hand blender, taking care not to create any air bubbles.
Place in a piping bag and pipe mixture into sphere molds and leave to set overnight in the freezer. Remove from molds.
Truffle Coating
Melt the 20 g Guittard Onyx 72% Dark Couverture Chocolate Wafers and use the temperature curve method to temper the chocolate.
Dip coffee ganache balls into tempered chocolate and remove any excess by hand.
Roll in the 10 g Guittard Cocoa Rouge 22/24% Dutched Cocoa Powder. Sift to remove any excess.