This preserved lemon recipe from chef Paula Wolfert's "Mediterranean Clay Pot Cooking" is used to make her Moroccan Fish Tagine.
Place lemons in a medium bowl. Sprinkle with salt and toss to coat. Transfer to a clean 1-cup glass jar with a lid; add lemon juice. Cover jar and let stand at room temperature for 7 days, shaking jar daily to distribute salt and juice.
To store lemons, add enough olive oil to cover and refrigerate for up to 1 year. Rinse lemons before using.