Meyer lemons are the lemon of choice in North Africa (and lovely they are) but they’re hard to get and I rather like the thicker skins of a common Lisbon lemon.
A measured teaspoon is 5 gm. Use 12 teaspoons of salt for every 5 lemons (i.e. 4 tbsp).
(Just ordinary salt)
Tradition is good but sometimes there’s a more practical way. Some recipes may tell you to keep lemons whole (slitting them lengthwise with two inter-crossing cuts, nearly to the bottom). That’s fine if you’re doing your lemons in huge jars or barrels. It’s much more practical to cut them into 8 crescents. They stack better and come to maturity more quickly and you can put them in manageable-sized jars. (The jars above are excellent having a glass lid which will not corrode. They are wide at top, making it easy to get you hands or food tongs in. (They will be available if you look. I found mine at Aldi. WECK preserving jars.)
Arrange the slices (crescents) in the jar, spooning over salt as you build the layers. You'll soon get the hang of how much, to finish with just enough for the final layer.
Close the jar and set aside for 2 days.
After this time, you will see that the lemons have given up a lot of juice. It the lemons are not covered by juice, be prepared to juice some more to cover. You may find a way to hold them below the surface of the juice. The juice or lemons should not touch a metal lid.
The salt will react with the lemons and make them silky, even slightly oily. This is the natural pectin. My batch is only three days old. If the salt you can see on the nearest slice does not dissolve, I will be annoyed with myself. Salt remaining after a week tells you you have over-salted. This is a waste of salt. Even if you love salt, salt cannot get saltier.
They will be ready in a month.
I'm assuming you're using lemons from an overloaded tree. If buying lemons (and nothing wrong with that) give them a light scrub if they've been polished with wax.)
You'll find many recipes using these (chicken with green olives and preserved lemon is a classic) and they can be chopped or slivered into salads. Take one out of its brine, detach the pulp and discard. You only use the skin.
This also works well with limes but I've not had great joy with oranges. Cumquats (cut in half) are glorious and look very special.
In the photo, you'll see Hawaiian red salt and some handsome looking extra large pyramid crystals (larger even than Maldon salt). More on that later.