Salsa Verde (Tomatillo Salsa)

recipe adapted from here
Ingredients 
1 lb tomatillos (about 12 medium), husked and rinsed 
2 korean chilli pepper - stem removed only, for extra spiciness
½ cup chopped white onion (about ½ medium onion) 
¼ cup packed fresh cilantro leaves
2 tbsp lime juice
1 teaspoon salt, to taste

Method

1. Preheat the broiler in the small oven. Place the tomatillos and chilli peppers on a baking tray and broil until they’re blackened in spots, about 5 minutes.
2. Flip over the tomatillos and chilli peppers with tongs and broil for 4 to 6 more minutes, until the tomatillos are splotchy-black and blistered.
3. Meanwhile, in a blender, combine the chopped onion, cilantro, 2 tablespoons lime juice and 1 teaspoon salt. Once the tomatillos are out of the oven, carefully transfer the hot tomatillos, peppers and all of their juices into the blender.
4. Pulse until the mixture is mostly smooth and no big chunks of tomatillo remain, scraping down the sides as necessary. Season to taste with additional lime juice and salt, if desired.
5. The salsa will be thinner at first, but will thicken up after a few hours in the refrigerator, due to the naturally occurring pectin in the tomatillos.