1) First of all, the broiler needs to be preheated.
2) Two baking sheets must be lined with foil the same one through two broiling rounds.
3) The tomatillos should be husked and rinsed. (You must realize that tomatillos have a tackiness to the skin and you may not be able to rinse it off).
4) Unpeeled garlic clove, chilies and tomatillos must be placed onto the baking sheet that is prepared.
5) Now, the baking sheet needs to be placed under the broiler and you must check them every one or two minutes until the chilies and tomatillos charred. (Generally speaking; 7 to 10 minutes are needed for tomatillos and chilies char a bit earlier).
6) Then, you must take a food processor and the onion pieces should be added to the bowl of the processor.
7) When you are finished with the tomatillos, allow to cool for a few minutes before placing them onto the bowl of the processor.
8) The garlic clove contents need to be squeezed out of their skin into the processor bowl. (The peel should not go into the salsa).
9) The top part of the chilies has to be removed using a sharp knife and discarded.
10) The chilies have to be sliced lengthwise before opening them and removing the inner membrane and seeds.
11) The chilies should be added to the processor.
12) Salt and cilantro must also be added and the processor must be turned on for pulverizing to the consistency of a liquid salsa.
13) If you are interested in creating some visual appeal, you can add some red sweet peppers.