There has been quite a lot of interest in the matter of my preserved lemons, and this afternoon I decided I needed a soothing study break activity, so I made a fresh batch and have chronicled the process for you. It's really very, very simple and foolproof; the hardest part is waiting for the lemons to finish preserving.
First I took a two-pound bag of organic lemons and washed and dried the contents. (You need lemon juice later on, too; I cheat and use bottled juice, though the recipes I've seen tell me not to. If you want to be particularly pure, you'll need to buy more lemons for juicing.)
This was enough fruit to fill three pint jars, which were meanwhile being sterilized by a trip through the dishwasher. Since you'll be eating the peel, it's best to get organic fruit if you can. You should of course wash them in any case, but you should be careful to wash and even scrub them quite thoroughly if they are conventional, and especially if they may have any wax on there.
Next, I quartered the lemons and tossed them with about a quarter-cup of salt. More salt is added later -- this is not a recipe to embark on if you're short on salt. There's definitely no need for any fancy salt here. Kosher salt, Morton's salt, any of that is fine. Your fancy flakey sea-salt should be saved for some other occasion.
Put a tablespoon of salt at the bottom of each jar and pack in a layer of lemon quarters, pushing them down. Sprinkle generously with salt and add another layer. Salt these again, and so on. Plenty of salt is the order of the day. I used about 1/3 cup additional salt in this step, on top of the original 1/4 cup.
Fill the jars to within 1/2" of the brim with juice, and close tightly. (I actually wound up putting a little more juice in these jars after I took the picture. Fill 'em up.) Don't process these as you would jam -- all that heat would change the texture of the lemons. Just close them and line them up on your counter. They need to sit at room temperature for at least three weeks, during which time you will give them a good shake once a day. Eventually they'll be limp and slightly translucent. The juice turns thick and syrupy, though not sweet, from the lemon oils. The pulp will be soft and jelly-like, and the rind will be ready for chopping and eating. The pith comes away from the peel very easily at this stage, and it's the only part you don't want to eat.
The mixture is far too acidic to have any risk of botulism. I'm told that even after you've opened the jar again following the fermentation process you don't have to refrigerate it, though if you have lemon bits sticking up out of the juice they can discolor. A sort of white lacy substance does sometimes appear in the liquid; this is just a precipitate of oils, salt, and stuff from the pith. Shake the jar and it will go away. I do keep mine in the fridge once they're done, because why not, and after all, it isn't really properly canned. Besides, counter space is limited. But you can do as you like.
Next: But what do I do with these lemons once I have them?