Wash and peel the iyokan citrus. Boil the peels in plenty of water. When the water comes to a boil, turn the heat down low and simmer for a while. Drain the peels in a colander and rinse the peels under running water while gently pressing them.

Repeat Step 1 two or three times, then remove the pith with a knife. If you blanch the peels, the pith will be easy to remove.

Blanch one more time and drain the water.

While you're blanching the peels, place the Iyokan flesh in a bowl.

Thinly slice the peel and place it in a cooking pot. Add the flesh and sugar, and let it sit for a bit. If you don't have much time, you can start simmering the marmalade it right away, but if you can, let it sit overnight. The liquid from the fruit will be released, and the fruit will absorb the sugar.

Once you start simmering the marmalade the liquid will be released and the fruit flesh will come apart.

Simmer on a medium heat for about 30 minutes and finish by adding the lemon juice and honey. Although it may seem like too much liquid, if you cool the marmalade it will become just the right consistency.