Jacques Torres's Tempered Chocolate
Here's the easy way to temper chocolate in the microwave. Jacques Torres demonstrated this technique on Episode 501 of "Martha Bakes."
Use European chocolates, with a higher cocoa butter content, and pistoles or callets for easier tempering.
Dark chocolate is the easiest chocolate to temper, so start there and work your way towards white and milk.
Make sure to fully submerge the immersion blender when blending the chocolate, so that you don't aerate the chocolate.