Sanitize your jar and fermenting weight in the oven at 180 for 3-5 minutes.
Put a tablespoon of pink salt in the bottom of your jar.
Place the lemon nose up and stem down on a cutting board and slice down from the top, stopping about 1/2 inch from the bottom. Rotate the lemon 90 and slice down again, making a cross or + shape.
Open the lemon slightly and sprinkle salt in the flesh on both sides and then open it the other way and sprinkle with more salt. Place in the jar and press down.
Repeat with each lemon until you get about 1/2 way and press it down until the juices cover the rinds.
Sprinkle a bit more salt as well as your peppercorns and other spices if using. I usually slide the tip of a couple bay leaves and a cinnamon stick into the edge of the jar at this point.
Repeat the slicing and salting until the jar is filled and then press down with your rolling pin again. Add more lemons if needed or squeeze some lemon juice in to cover the top. Press down again until you have about 2" room at the top.
If needs be you can break them apart to fill the gaps.
Once the liquid covers the lemons, place your fermenting weight in the top and seal the jar.
Write the date on the bottom and leave to ferment for a month!
When you want to use a lemon for a recipe you'll most likely want to rinse it (the Moroccans do). Use them sliced up in a dish or if you're one of those crazies like me just eat them chopped up in a salad.