Crumble half of Million Dollar Pound Cake into a large bowl; stir in Vanilla Buttercream Frosting, 1/3 cup finely chopped crystallized ginger, and amaretto liqueur until mixture holds its shape. Shape into 1-inch balls, and place on wax paper. Pour water to depth of 1 inch into bottom of a double boiler over medium heat. Bring to a boil; reduce heat, and simmer. Place bittersweet chocolate and semisweet chocolate in top of double boiler over simmering water. Cook, stirring occasionally, 15 minutes or until melted. Remove from heat. Dip truffles in melted chocolate; place on a wax paper-lined baking sheet. Sprinkle immediately with finely chopped crystallized ginger.