What is a preserved lemon.
Preserved lemons are a staple of Moroccan cooking. They are easy to make by cutting the lemons lengthwise (from stem end to base) almost all the way through into quarters, so the lemon is held together at one end. The lemons are then stuffed in a jar and covered with salt and lemon juice. Leave them to cure in the brine for several months and they develop a mellow, sweet lemony flavor. To use, rinse the salt off the lemon and discard the flesh. Chop the peel and it can be used to garnish all sorts of dishes: Moroccan stews, chicken tagines, salads, soups. It's really tasty kind of like an olive but different. You can also buy jars of preserved lemons.
It can be cured in as little as three weeks, months just make it nicer!
I just wanted to add if you are trying to buy them they can be labeled as "pickled lemon." Learned that one the hard way lol.