Cut off the little rounded bit, or nib, at the stem end of each lemon.

Hold lemons over a plate or bowl to catch any juice. On the end opposite the nib, make a large cut by slicing lengthwise downward. Make a second downward slice, so you’ve incised the lemon with an X shape. Avoid making the cuts so deep that the lemon separates into quarters.

Pack salt into the lemon where you made the cuts. Be generous; use about 1 tablespoon salt per lemon.

Put a couple of tablespoons of salt in the bottom of a sterilized quart glass jar with a tight-fitting lid. Add the salt-filled lemons, packing fruit in layers, and sprinkling a thin layer of salt between each layer. Push the lemons down firmly to pack them tightly and to help express some of their juice. I used a pestle from a mortar and pestle set to help shmoosh the lemons into the jar.

(Optional) If you desire, add a Safi spice mixture—a few coriander seeds, a bay leaf, a dried chili, and a cinnamon stick, or any combination of these. Finish with a final layer of salt. Cover the jar tightly and let stand overnight.

The next day, press lemons down again. Encourage them to release more juice as they begin to soften. Repeat for 2 to 3 days. Add more freshly-squeezed lemon juice if necessary, lemons must be completely covered with salted lemon juice. After about a month, the preserved lemons will be soft and ready to use. While preserved lemons are kept in pantries in North Africa, most U.S. chefs recommend keeping them under refrigeration where they will last for months.