Wash the Meyer lemons well. then slice each one in half lengthwise. Use your knife to remove the inner white pith that runs down the center, the use your fingers to scoop out any seeds. Reserve the seeds, then cut each half in half again lengthwise. Use a very sharp knife to cut each lemon quarter into very thin slices - make them as thin as you possibly can.

Add the lemons to a medium saucepan along with the sugar, water and salt. Take the reserved lemon seeds and lightly crushed green cardamom pods, place them in a small piece of cheesecloth, and tie it with a piece of kitchen twine. Add it to the pot, and bring it up to a boil. The lemon seeds are high in pectin, which will help to set the marmalade. Reduce the heat to a simmer and cook for about 20 minutes, until the lemons break down and the liquid reduces quite a bit. It should be thick and syrupy. Allow the mixture to cool.

Remove the lemon seeds and cardamom pods, then transfer the marmalade to a jar (or jars). Cover and keep refrigerated for up to 1 month.