Wash the lemons well. Cut the lemons in quarters lengthways from the pointed end, but only cutting to within 1cm of the base.
Place 2 tablespoon salt in the base of a large sterilised jar. Pack about 1 teaspoon of salt into each lemon, pressing well into the cut edges. Make sure you do this on a plate so that you can capture all the juices that run from the lemons.
Pack the lemons into the jar tightly. Cover with a sprinkling of more salt. Place the lid on the jar.
Leave at room temperature for four days, by which time the lemons will probably have exuded enough juice to now cover the lemons. If not, simply add more lemon juice until it does.
Pour a thin layer of olive oil over the lemons. Make sure the lemons are entirely covered. If this poses a problem, press a piece of crumpled baking paper down under the lemon juice, ensuring that no air bubbles are trapped under it. This can be removed after a week or two and the lemons should stay submerged. If not, repeat the process.
The lemons will be ready to eat in a four weeks.
Generally only the rind is used in cooking and the pith and flesh discarded.