From America's Test Kitchen
The problem with many homemade truffles is that they have a dry, grainy texture. There are three keys to creating creamy, silky-smooth truffles. First, start with melted chocolate. Melting the chocolate before adding the cream allowed us to stir—rather than whisk—the two together, reducing the incorporation of air that can cause grittiness. Second, add corn syrup and butter. Corn syrup smoothes over the gritty texture of sugar, and butter introduces silkiness. Finally, cooling down the ganache gradually before chilling prevented the formation of grainy crystals.
Makes 64 truffles
In step 3, letting the chocolate to rest on the counter for 2 hours allows it to “cure”, and contributes to its creamy texture. In step 5, running your knife under hot water and wiping it dry makes cutting the chocolate easier. In addition to the related variations, the truffles can be flavored with 2 tablespoons of your favorite flavored liqueur. We recommend using one of the test kitchen’s favorite baking chocolates, Callebaut Intense Dark L-60-40NV or Ghirardelli Bittersweet Chocolate Baking Bar for this recipe. If giving the truffles as a gift, place each one in a 1 1/2-inch candy cup liner and then place the truffles in a gift box. Keep refrigerated until giving.