Boil the pork leg in water for 2 hours with peppercorns and bay leaf if desired. I didn't place any, as I will be using the broth for pet food prep.

Once cool, place it in the fridge overnight. This will help it dry. The key to making it crunchy is that it should be dry before air frying it. So avoid condensation if you place it inside a container. I don't cover with a lid.

Next day: if you're ready to air-fry, take it out of the fridge and poke all over and all sides with a fork.

Pre-heat the AF for 5 mins at 150 deg C.

While pre heating, cover/rub all sides with rock salt. This will help it puff up and make it crunchy.

Note: since we didnt add salt during boiling, this will not make it salty. And its rock salt, so you can easily tap away the extra salt before serving.

Place on the top rack or arrange so it's near the heating element. Air-fry for 20 minutes at a time at 200 deg C.

I have a small AF (9L) so I have to do it 20 mins at a time, turning it on each side so all sides will have the crunch.

Note: no need to spray with oil. It actually does not help in making it puff/crunchy since it needs to be dry.

Tap with a fork to check if crunchy to your liking. If some parts still lack the cook, point that towards the heating element and air-fry for 5-10 mins more.