Melt the chopped chocolate in a double boiler or in a heatproof bowl set over a pot of simmering water. Alternatively, melt the chocolate very carefully in the microwave by heating in 30-second intervals at 50% power. The key to easily dipping the truffles is to achieve the correct consistency of chocolate. Make sure your melted chocolate is fairly thin. If the chocolate is thick, add small amounts of vegetable shortening (such as Crisco) to achieve the correct consistency.
Remove only a few truffles at a time from the freezer. Dip each chilled truffle, one at a time, coating in chocolate and shaking gently to remove the excess. To facilitate dipping, take a wooden kabob skewer and use it to pick up a truffle, swirl the truffle in the chocolate, then transfer the dipped truffle to a wax-paper lined surface. Twist the skewer back and forth to remove it from the truffle. You can also use a fork to help remove the skewer. The optional mini-chocolate chip garnish will hide any imperfections left behind. Alternatively, you can use two forks to roll the truffle around in the chocolate and then, lifting the truffle out with the forks, let the excess chocolate run off. Note: If at any point during dipping, the cookie dough balls become too soft, return to the freezer to chill for 30 minutes.
If using mini chocolate chips for garnish, sprinkle on top quickly after dipping each truffle before the chocolate sets.
Once all the truffles have been dipped, store them in the refrigerator (or freezer) until ready to serve.