On the Stovetop
1. Using a large knife, chop the chocolate into large chunks and transfer to the top pan of a double boiler.
2. Set the top pan of the double boiler over barely simmering water in the bottom pan. Make sure the water does not touch the bottom of the pan holding the chocolate. Do not let the water boil. Any moisture or steam that comes in contact with the chocolate could cause it to seize, or stiffen.
3. As it melts, stir the chocolate every now and then with a wooden spoon. When the chocolate is liquefied, remove the top of the double boiler from the bottom and set aside to cool slightly, unless otherwise instructed in a recipe. Do not cover the chocolate as it cools.
In a Microwave Oven
1. Chop the chocolate into large chunks and transfer it to a microwave-safe dish.
2. Heat the chocolate on medium (50% power) and check it after the first minute.
3. Keep checking it every 30 or 40 seconds to prevent scorching.
4. When the chocolate looks shiny and softened, remove it from the microwave. It will not melt completely in the microwave but will become smooth and liquid upon stirring.
Adapted from Williams-Sonoma Kitchen Companion (Time-Life Books, 2000).