If you want a smooth, shiny finish to your chocolate once it sets up, you have to temper it. Don't use chocolate chips - they're designed to hold their shape.
I would recommend a high quality chocolate like Valrhona - I've seen it at Trader Joe's. You could also use Baker's brand chocolate. To temper, you have to melt it to a certain temp, cool it, then re-melt it. I will do a search and post a link if I find the exact methods.
Here you go!
Tempering Real Chocolate
by Pam Williams
Over the next two lessons we are going the explore the production of chocolates. In this lesson we will look at the art of tempering real chocolate in order to enrobe assorted fillings and mold chocolate items in the following lessons. When purchasing chocolate, you have a choice of two different types of chocolate products: real chocolate or confectioners coating. Confectioners coating was developed by chocolate manufacturers to ease the enrobing process. The cocoa butter was removed from the chocolate and a vegetable oil, mainly palm kernel oil, was added. The product looks just like real chocolate but cannot be sold as such because it doesn't contain cocoa butter. There were two reasons for this replacement. Palm kernel oil is 1) cheaper than cocoa butter which makes volume chocolates more affordable, and 2) it allows the coating to enrobe or be molded without tempering. You can substitute a good quality confectioners coating for real chocolate in the recipes in the next three lessons and skip the tempering step. But if you want the flavour and texture of real chocolate, please continue to read about tempering.
Cocoa butter makes up anywhere from 50-60% of the real chocolate mass. The cocoa butter crystals remain in suspension with the cocoa powder or solids until the chocolate is heated. Once you have heated the chocolate, this suspension is broken and when the chocolate cools, the cocoa butter crystals rise to the surface producing white streaks or a gray dusting on the surface of the chocolate.
You've probably encountered chocolate with a dusty look. This means the chocolate was exposed to heat (a warm truck during shipping or a warm storage cupboard). While it won't really effect the taste of the chocolate, it does make for a unappetizing appearance.
Tempering returns the cocoa butter crystals to suspension within the chocolate mass and produces a chocolate with a dark glossy appearance and a firm consistency. There are many processes used for tempering but I have found the following to be most reliable. You will need a double boiler (I've used a metal bowl over a shallow sauce pan if a real double boiler wasn't available), a candy thermometer that will register low temperatures to 28ØC/82.4F, a rubber spatula and at least one pound of semi-sweet, milk or white chocolate chopped into small pieces.
Melt 2/3 of the chocolate in the double boiler over hot, but not simmering, water that is not touching the bottom of the container holding the chocolate. (Remember, the biggest enemy of real chocolate is heat, so don't let the water get too hot.) Melt the chocolate until it reaches a temperature of approximately 45C/113F. Remove the top of the double boiler containing the chocolate and place it on a towel on the counter. Beat in the remaining 1/3 of chopped chocolate letting the mixture cool to approximately: 31C/87.8F for semisweet chocolate, 29C/84.2F for milk chocolate, and 28ØC/82.4F for white chocolate. Mixture should be smooth and glossy. Hold at that temperature by moving the container on and off the hot water while you dip or mold your chocolates.