Aside from the lightning bolt scar on his forehead, Harry Potter's most identifying characteristic are his glasses. When making a Harry Potter themed cake, you may choose to include Harry's glasses in your design. Using chocolate fondant rather than dying white fondant will make it easier to get a black shade. Once you get your pieces rolled out to the right width, making Harry Potter's glasses is just a matter of joining the pieces together like a puzzle.
Find a picture of the Harry Potter glasses and print it out. You will use this image as a model for your fondant creation.
Dye your chocolate fondant black using your gel food colouring. Start with three drops and add more as necessary until you reach your desired shade.
Roll out four 4.5-inch-long pieces of fondant. Each piece should be an even width, about 1/4 inch each. Cut off the ends to make each piece 4 inches long total. Roll out one 3/4-inch piece for the part of the glasses that rests on the bridge of the nose. Reserve the remaining fondant in an airtight container.
Make a circle with one of your rolled pieces of fondant. Make a second circle. Compare the two to make sure they're even.
Take the two other pieces and bend them at one end to make the ear pieces of the glasses. Make the nose piece curved in the shape of a fingernail, using your photo for guidance. Allow all the pieces to harden for an hour or two hours depending on the humidity in your kitchen.
Use small dots of icing to join your fondant pieces. Then, use your reserved, still-moist fondant to blend the joints. Set the finished glasses on a soft, forgiving surface so that none of the pieces flatten as they set.