Mix the miso and maple syrup together very well to form a smooth paste. Spread the paste over the middle of a piece of cling film/plastic wrap that is big enough to wrap the egg inches.
Put the egg in the middle of the cling film, and wrap it around the egg. Twist the plastic shut at the top, and gently squish the miso so that is completely covering the egg.
Put the wrapped eggs in a plastic container, and leave for at least 5 hours and up to a week in the refrigerator.
When you are ready to use an egg, take off the cling film. The white of the egg should be a light to medium beige. The surface will be covered with a bit of miso. You can leave this on, or wipe it off gently for aesthetic reasons if you like.