Keep chocolate wrapped in a tightly covered container or sealed plastic bag in a cool, dry place. If stored in a place where temperatures reach higher than 70° F, chocolate may "bloom" or develop a harmless gray film.
Keep cocoa powder in a tightly covered container in a cool, dry place.
In the microwave: Place 1 cup chocolate pieces or 6 ounces chopped chocolate in a microwave-safe bowl. Microwave, uncovered, on 70 percent power (medium-high) for 1 minute. Stir, then microwave on 70 percent power for 1 1/2 to 3 minutes more. Stir every 15 seconds until the chocolate is melted and smooth.
On the stove: Place chopped chocolate or chocolate pieces in a small heavy saucepan over low heat. Stir constantly until chocolate just begins to melt. Remove saucepan from heat and continue stirring until smooth.
Coarsely Grated Chocolate: Rub a cool, firm square of chocolate across the large section of a handheld grater.
Finely Grated Chocolate: Rub a cool, firm square of chocolate across the fine section of a handheld grater. Clean the grater often to prevent clogging.
Chocolate Curls: For large curls, draw a vegetable peeler across the broad surface of a bar of room-temperature chocolate (milk chocolate works best). For smaller curls, use the narrow side of the chocolate bar.
Chopped Chocolate: Place chocolate block on a cutting board. With the widest part of a chef's knife, press down on the chocolate to break it into big chunks. To chop into smaller pieces, hold the tip of the knife in one place and make small chops with the back of the knife, moving side to side.