I have a love-hate relationship with making chocolate confections. On the plus side, it's challenging, fun to do and, if done right, the results are beautiful, impressive and delicious. On the minus side, it's messy and, if done wrong, the chocolates can look ugly (although often they still taste delicious).
The secret to beautiful, shiny chocolate that's firm at room temperature and has a good "snap" when bitten into or broken is tempering. The word is not derived from "temperamental" - although that adequately describes chocolate when it is being cooked; rather, tempering refers to heating, cooling and re-heating to precise temperatures so the cocoa butter forms minuscule, evenly sized crystals.
If chocolate is not tempered properly it can become dull with white streaks, and the texture will be crumbly and soft. Dark, milk and white chocolate all need to be tempered to different temperatures.
Chocolate "seizes" if it comes into contact with moisture: it becomes stiff, lumpy and dull. In the old days, chocolate, which burns easily, was melted over a double boiler, but you had to be careful that no condensation dripped into the bowl holding the chocolate.
It's much easier to use a microwave, but you have to watch it. Microwave the chocolate on high, stirring every 30 seconds, then about every 15 seconds after it's 50 per cent melted. Take the bowl from the microwave when the chocolate is about 80 per cent melted and stir so the residual heat melts the remainder before checking the temperature.
Skilled pastry chefs can gauge the temperature just by putting some of the melted chocolate under their lower lip (which is very sensitive); the rest of us can use an instant-read thermometer.
Your preparation can be cooled either by adding finely chopped chocolate or by pouring the melted stuff onto a marble slab and working it back and forth with a palette knife until it's at the right temperature.