Wash the jars and their lids thoroughly and sterilize them with boiling water
Wash the lemon thoroughly, ideally using a brush, and then pat dry. Set one lemon aside and cut off both ends of the other
Cut the lemons lengthwise from one end, close to the stop but not all the way through. Turn them over and cut the other side in the same way, but this time offset by 45° from the cut at the other end
Fill each incision with a spoonful of salt and carefully place them in the glass. Place all the lemons close together in the glass and press firmly to minimize the space between them
Fill the glass with previously boiled and slightly cooled water (lukewarm) until everything is covered, add the juice of one lemon and seal tightly
Store in a dark place at room temperature for approximately 4-6 weeks. Then open and enjoy!