There are a couple of ways to make this. The period translations read:
Pickled lemons are done in the manner thus; Slice lemons. Sprinkle with salt. Drain of juice. Place in water or oil.
The lemon is split lengthwise and then filled with coarse salt. It is left thus for two nights and then kept in lemon juice covered with oil.
(Rodinson, pp. 144)
½ cup salt
Oil or water to cover
The first way to do this is to cut lemons in either round or length wise. When doing round cuts I remove the ends. When doing lenthwise cuts I leave the ends and the seeds (these will either be ground up if using a blender or pop out on their own if hand chopping).
Quartered…ok sixes or rounds. Either way is perfectly except-able. My preference is for rounds though I do not get as many pieces visually.
Once the lemons have been cut, place them in a large bowl. Toss the salt and the lemons together till all the slices are coated then leave to “juice” for 48 hours (roughly). after the salt has had it’s purgative effect, rinse off under water, draining the excess water thoroughly. Place the slices in a clean jar and cover with either water or olive oil. Do NOT cover with both. Really! As the old saying goes water and oil do not mix (and this would just be baaad for the lemons).
I used a jar I had on hand (artichoke hearts were really tasty!) for the lemon rounds and an olive oil.
Which ever method is chosen make sure the lemons are covered completely. The covering of the lemons, even though very acidic already, is necessary as there is the potential of mold growing on the fruit. Once the fruit is completely covered the chances is cut down dramatically.
If slices should become covered in mold, simply pull the offending pieces out of the oil or water and top off with a little more liquid. It has been my experience that the fruit can stay preserved this way for 1 to 2 years. (This may not be the average in every household) As with all non heated/sealed foods be cautious in usage. If you suspect some thing is off do not use.