Spread the tomatillos out on the lined baking sheet stem side down. Place under broiler until charred, about 6 to 8 minutes. Some will crack and release juice, and that’s ok. Add tomatillos and juice to the blender jar.
On a dry skillet, toast the onion, chile, and garlic, turning until charred on all sides. Add to the blender jar. (Note: Remove the seeds of the chile if you want a milder salsa.)
Add the cilantro and lime juice to the blender jar. Blend all for a few seconds. Pour into a large bowl and serve, or pour into jars and refrigerate for up to 1 week. Can also freeze in plastic containers. I use the Ball Plastic Freezer Jars.