Remove the papery husks from the tomatillos. Tomatillos have a sticky coating under the papery husk. Remove the husk and soak the tomatillos in warm water for about 50 seconds. Afterward, rinse them by hand. This is an important part of making the finished salsa so don't skip it!
Pat each tomatillo dry with a paper towel and set aside.
Preheat the oven to the high broil setting.
Cut tomatillos in half and place them cut side down on a foil-lined baking sheet.
Broil tomatillos in the oven on high for 5-7 minutes. When tomatillos are done the outer skin will have a slightly blackened appearance and look charred and toasty.
Remove from the oven and let the tomatillos rest until completely cooled. Reserve all the juices that have collected during cooking on the foil. This is another important part of making the finished salsa.
On another sheet pan broil the whole Anaheim chilis along with the garlic cloves (still in their skin) in the oven, turning once until blackened on both sides and the skin appears to lift. This will take about 3-5 minutes per side.
Let the chilis and garlic cool completely, then remove the skin, seeds, and stems from the chilis, and remove the skin from the garlic. Set both aside.
Halve the jalapenos, remove seeds and ribs to the spice level desired, (see chart in post to choose your spice level), roughly chop, and set aside.
Clean, dry, and chop off the stems from the cilantro, and set aside.
In a blender or food processor place roasted cooled tomatillos with skin, accumulated juices, chilis, jalapenos, garlic, onion, cilantro, lime juice, salt, pepper, and red chili flakes. Turn blender or processor on low for a few seconds, then turn it up to high and blend well until all ingredients are mixed together.
This salsa is best when you make it ahead of time because that allows all the flavors to meld and pop which makes an incredible tasting Salsa Verde!