Tempering -- a technique that stabilizes chocolate -- creates a glossy sheen and a crisp snap in the finished candies.
Source: Martha Stewart Living, December 2008
Yield Covers about 70 Caramallows
1 1/2 pounds bittersweet chocolate, chopped, divided in portions
Bring a saucepan with 2 inches of water to a simmer, and then turn off heat. Set bowl with chocolate over saucepan, and let melt, stirring gently with a rubber spatula until chocolate registers 118 degrees on a candy thermometer. (Watch the chocolate carefully, as heating and cooling times can vary.) Remove bowl from saucepan.
Add pound unmelted chocolate to bowl and stir until chocolate cools to 84 degrees. (Remove any unmelted pieces with spatula.) Return bowl to saucepan, and let stand, and stir until chocolate registers 88 to 90. Use immediately. Repeat with remaining chocolate.
Temperatures for tempering vary among chocolates, so you may want to check the package or call the manufacturer. Tempering chocolate can be tricky, but a few tips will help: Don't use a wooden spoon to stir, don't let any water get into the chocolate, and be sure the thermometer tip doesn't touch the bottom of the bowl. Because of the large amount of chocolate called for in this recipe, it's easier to make half a batch at a time. Tempered chocolate should be used immediately.