If you are using high-quality chocolate that is already tempered, you might be able to use a shortcut and avoid going through the whole tempering process. By carefully melting the chocolate at low temperatures, it is possible to retain the temper. First, ensure that your chocolate is indeed tempered: carefully examine the surface, making sure that it is glossy, smooth, and without streaks or blemishes. Next, break the chocolate, making sure that it has a crisp “snap” when broken, and that the texture of the inside of the chocolate is uniform. If all of these conditions are met, you can attempt to melt the chocolate while keeping the temper.
The Shortcut Method
To use this method, chop one pound of tempered, semisweet chocolate in coarse chunks. Microwave it at 50% power for 3 minutes, stopping every 30 to 45 seconds to stir the chocolate with a rubber spatula. Remove the chocolate when 2/3 of it has melted, and stir the chocolate until the remaining chunks are fully melted. If the chunks do not melt, warm the chocolate again very briefly.
What's the Temperature?
Check the temperature with a chocolate or instant-read thermometer. If it is less than 90 degrees (88 degrees for milk or white chocolate), it is still in temper and ready to be used.
The Spot Test
Remember to do a spot test to make sure: spread a spoonful thinly over an area of waxed paper and allow it to cool. If it is tempered, the chocolate will harden within 5 minutes and look shiny and smooth. If it is dull or streaky, it has lost its temper, and you should temper the chocolate again.