Heat your oven to 275°F (140°C). Wash your jars with soap and water and dry. Place in the oven on a baking sheet for 15 minutes. Remove, and let cool to room temperature (about 10 minutes).
Juice half (8) of your lemons. With the other half, cut four slits lengthwise into each lemon, stopping about an inch from the top/bottom at each end. Stuff each lemon with a tablespoon of salt.
In your jars, place half in each of: bay leaves, peppercorns, coriander seeds, nigella, and a whole cinnamon stick in each. Press your salted lemons into the jar as tightly as possible. Pour in your lemon juice. Don't worry if they are not covered. Close the lid.
Let sit on your counter at room temperature overnight. In the morning, press the lemons down again, so that they are submerged in the juice. Place a canning weight in each jar, screw on the lid, and leave in a cool, dark place for at least thirty days.
While you only use the peel of the preserved lemons in most recipes, the innards can be rinsed and blended into salad dressings or sauces. It is however very salty, so take care to check the taste before adding a lot / more salt.