Sterilize your jar (or jars): I do this by placing the jar in a clean sink and pouring about 8 cups of boiling water over the jar. Alternatively, pour the boiling water into the sink and submerge the jar. Remove the jar to a clean towel on the counter with tongs and allow to cool to room temperature.

If not done already, dice your onions, and husk and rinse your tomatillos.

Line a baking sheet with parchment paper and place the tomatillos and jalapenos on it.

Broil the tomatillos and jalapenos until a few black spots and blisters begin to appear, then flip them all and place back under the broiler for another minute or two. Remove from the oven and let sit for a couple minutes on the baking sheet.

Add your onions, cilantro, lime juice and salt to a food processor and pulse until well blended.

Using tongs, transfer your roasted tomatillos and jalapenos to the food processor and continue to pulse until the whole mixture is well blended.

Transfer to your prepared jar or jars and lightly cover. Allow to sit at room temperature to ferment for about 2-4 days.

Begin tasting after 2 days or so: you should be able to see a few tiny bubbles scattered throughout the salsa. The flavors will have mellowed out and melded. At a cool room temp, I find this salsa to be perfect after 3 days.

Once it's done fermenting, tightly cover the salsa and transfer it to the fridge. It should keep there for several months.

Enjoy!