I imagine most of us are familiar with preserved lemons — the sort we associate with Morocco, although it isn’t a process exclusive to North Africa; I have found similar all over Asia and the Americas too. The usual method is to leave whole or almost quartered lemons to steep in heavily salted water or lemon juice. This is extremely simple to do — it just requires a certain amount of patience. Simply top and tail the lemons (or limes, or Seville oranges — you need a fairly acidic fruit for this), then cut a deep cross through each one, almost — but not quite — to the base. Stuff each lemon with sea salt (around 2 teaspoons in each), then pack tightly into a sterilized preserving jar. Weigh the fruit down if possible — I find scalded muslin wrapped around traditional weights or a well-scrubbed tin works — then leave for a couple of days. Remove the weights, muddle the lemons a bit with a wooden spoon to try to release more juice (some will already have collected in the base of the jar), then top with freshly squeezed lemon juice until the lemons are completely covered. Seal, then leave to mature for at least 4 weeks. They can then be kept for over a year in the refrigerator once you have opened them. — Catherine Phipps, author of Citrus
You can add aromatics to the lemons when you add the lemon juice. Black peppercorns, cardamom, and bay leaves are all good.
For other citrus:
You can apply the same method to limes and Seville oranges. In fact, researching this solved a long-standing conundrum for me. I had always wondered what the “lime pickles” in Little Women were: you know the ones — used as currency amongst Amy March’s school friends and the source of a great humiliation when she is forced to throw them, two at a time, out of the classroom window. These, I think, are best cut through into quarters. Add 2 tsp salt per lime and leave to stand in the same way, then cover with lime juice, adding any aromatics. I like mace blades and allspice berries or cinnamon sticks and star anise, perhaps with a few dried chilli (red pepper) flakes sprinkled in. I have made them plain and tried to imagine a group of teenage girls wanting to chew on them, and can almost see it — they are salty, sherbet and mouth-puckering, and will make your mouth go numb in the same way as a bag of Haribo sours. So yes, strangely addictive.
Adapted from Citrus by Catherine Phipps (Quadrille, 2017, RRP $29.99 hardcover)