Weigh the pork loin and write down the starting weight. (Don’t skip this step—it’s critical for tracking weight loss during curing).
Place the loin on a large sheet pan and coat it evenly with kosher salt, making sure every surface is well covered.
Transfer the loin to a large food-safe plastic bag. Add the rosemary, garlic, Meyer lemon juice, and lemon slices, distributing the seasonings evenly around the meat.
Roll the bag tightly so the salt and aromatics stay pressed against the loin.
Set the bagged loin on a clean baking sheet. Place another pan of similar size on top, then add a weight (2–3 pounds) to press the loin evenly.
Refrigerate for 1 day per 2 pounds of meat.
Halfway through curing, flip the loin over. Rub the cure and seasonings back into the meat, roll it tight again, and return it to the press.
When the curing time is complete, remove the loin from the bag. Rinse thoroughly under cold running water and pat completely dry.
Rub the entire loin with ground fennel for a uniform, light coating.
Tie the loin with butcher’s twine (as you would for a roast) so it can hang securely in your curing space.
Hang the loin until it has lost 30% of its original raw weight that you recorded in step 1.