2 1/4 lbs. bittersweet chocolate, finely chopped
4 oz. milk chocolate, finely chopped
1 1/4 cups heavy whipping cream
1 1/2 tbsps. instant espresso powder
2 tbsps. Kahlúa or other coffee-flavored liqueur
3 to 4 tbsps. cocoa powder
60 candy coffee beans or mocha beans, for decoration
Place 12 oz. of the bittersweet chocolate and the milk chocolate in a 2-quart mixing bowl. In a 1-quart saucepan over medium heat, bring the cream to a boil. Remove the pan from the heat, dissolve the espresso powder in 3 tbsps. of the cream, then blend this mixture back into the rest of the cream. Pour the espresso cream into the bowl with the chocolate and let the mixture stand for 1 minute. Stir together with a rubber spatula, whisk or immersion blender until thoroughly blended. Stir in the Kahlúa and blend well. Cover the truffle cream, let cool to room temperature, and chill in the refrigerator until thick but not stiff (2-3 hours). Or let the truffle cream sit at room temperature for several hours or overnight until completely set and thick.
Line 2 baking sheets with parchment or waxed paper. Fit a 12-inch pastry bag with a large plain round pastry tip with a ½-inch opening and fill partway with the truffle cream. Holding the pastry bag 1 inch above the paper, pipe out mounds about 1 inch in diameter. Or use a small ice cream scoop to form the mounds. Cover the mounds with plastic wrap and chill in the freezer for 2 hours or in the refrigerator for 6 hours.
Dust your hands with cocoa powder and roll the mounds into balls. These will be the truffle centers. Cover and chill the centers for another 2 hours in the freezer.
Remove the truffle centers from the freezer and bring to cool-room temperature so that the outer coating won’t crack when they are dipped. Line 2 more baking sheets with parchment or waxed paper. Melt and temper the remaining 1 1/2 lbs. of bittersweet chocolate Place a truffle center into the tempered chocolate, coating it completely. With a dipper or fork, remove the center from the chocolate, carefully shake off the excess chocolate, and turn the truffle out on the paper. After dipping 4 truffles, center a candy coffee bean on top of each truffle before the chocolate sets up.
Let the truffles set up at room temperature, or chill them in the refrigrator for 10-15 minutes. When the truffles are set, place them in paper candy cups. In a tightly covered container wrapped in several layers of aluminum foil, the truffles will keep for 1 month in the refrigerator or 2 months in the freezer. The truffles are best served at room temperature.