Recipe adapted from Epicurious
~from Savoring Time in the Kitchen
4 ounces bittersweet chocolate, chopped
4 ounces semi-sweet chocolate, chopped
1/2 cup plus 2 tablespoons whipping cream
1 tablespoon cognac (or brandy)
1/4 teaspoon vanilla extract
1-1/2 cups of toasted hazelnuts, chopped small (reserve 1/3 cup for adding to truffle batter)
Place the chopped chocolate in medium bowl, preferably metal but I used an oven-proof glass bowl. Bring the cream to a simmer in small saucepan. Pour the hot cream over the chocolate and allow to stand for 5 minutes. Stir until smooth. Mix in cognac or brandy and vanilla. Cool for 30 minutes, stirring every 10 minutes.
Using an electric mixer, beat the chocolate/cream mixture until fluffy and lighter in color, about 4 minutes. Add 6 tablespoons of finely chopped hazelnuts. Cover and refrigerate until firm, about an hour or so.
Line a baking sheet with parchment paper or waxed paper. Place the remaining chopped nuts in another medium bowl. Dip a melon-baller into a glass of hot water and then into the cold truffle mixture, forming round truffle. (I had to round them with my hands afterward). Place the truffle into the chopped nuts and roll around to coat completely, pressing in the nuts so they stick. Place on prepared sheet. Repeat with remaining truffle mixture and nuts. Cover and chill until firm, about 1 hour.
Chocolate truffles can be stored, covered, in the refrigerator for up to two weeks or in the freezer for up to two months.