Wash the Meyer lemons thoroughly. Slice each one in half lengthwise.

Use a knife to remove the white pith that runs down the center of each half, then use your fingers to scoop out any seeds. Set the seeds aside.

Cut each lemon half in half again lengthwise, then slice each quarter into very thin slices—use a sharp knife and slice as thinly as possible.

Place the lemon slices in a medium saucepan along with the sugar, water, and salt.

Wrap the reserved lemon seeds and lightly crushed green cardamom pods in a small piece of cheesecloth, then tie it closed with kitchen twine. Add the sachet to the pot.

Bring the mixture to a boil over medium-high heat. Once boiling, reduce the heat to a simmer and cook for about 20 minutes, or until the lemons have broken down and the liquid has reduced to a thick, syrupy consistency.

Remove from heat and let cool. Discard the sachet of seeds and cardamom pods.

Transfer the marmalade to a jar or jars. Cover and refrigerate for up to 1 month.