After washing and spinning dry, I stripped all the leaves off and ran it through the food processer with 1/2 cup kosher salt and 4 small peeled garlic cloves. Pulse several times, it will be a little bit damp and clumpy (Yes, that's a word, even if I just made it up which I probably didn't because it is a very descriptive word and I'm sure others have used it).
Heat the oven to 170. Spread the salt mixture out on a large rimmed cookie sheet, into a fairly thin layer. Pop it into the oven, then turn the onion off. I let mine dry for 5 days, but mostly because I sort of forgot it was in there. Basically, let it dry until it is dry. You'll know.
Then, run it through a food processor or ninja type grinder again. It will be clumpy (It's a word!) and you want the salt to be fine.
When it is done, pour into spice jars. Use it to sprinkle on Chicken, Pork, or roasted veggies.
