Zest the lemons and the orange, making sure you don't get any of the white peel.
Add the sea salt and mix well.
Use your fingers to gently coax the citrus oils out of the zest.
Transfer the mixture to a baking sheet lined with parchment paper.
Pop it in a preheated oven set at the lowest temperature and bake for 10-20 minutes until all the moisture is gone.
Transfer to a clean glass jar and store for weeks, if not longer.
Notes
Make sure you wash and clean the citrus fruits you're using. I would recommend using organic ones for best results.
Zest the fruits carefully and make sure you don't end up scraping the white pith as it can taste bitter.
If you want to add other ingredients into the mix, you might need to blitz them first (along with the salt) in a food processor, and then bake them. I did the same when I used whole garlic cloves while making my garlic parsley infused salt.