Place the oven rack 3 inches from the top of the oven. Turn the oven to broil.

Cover a baking sheet with tin foil then coat it with cooking spray. Place the washed tomatillos on the baking sheet. Place into the oven under broil for 3-4 minutes, or until blackened. Flip the tomatillos over and place them back under the broiler for 2-3 minutes, or until blackened.

Remove from the oven and place the tomatillos in a large zip-lock bag. Seal and set aside for 5 minutes. Remove the blackened skin and place the tomatillos into a bowl. Set aside to cool to room temperature.

Place onion, serrano pepper, garlic, cilantro, and lime juice in the bowl with the tomatillos. Season with sea salt, to taste.

Blend the salsa with an immersion blender until smooth. Taste and re-season with lime juice or salt, if needed.

Set aside to allow flavors to mingle. Serve with tacos, chips, burritos, and eggs–the possibilities are endless!