Roast your vegetables in the oven by broiling: layer your vegetables evenly on a parchment paper lined baking sheet, including cut tomatillos (in half, so that they are arranged skin side up), unpeeled garlic cloves, jalapeno pepper, and onion.
Broil on high setting (if available) for about 8 minutes or until your vegetables get a nice, charred appearance. Remove vegetables that are charred faster than the others, if necessary, and continue until all vegetables are slightly charred and blistered. Alternatively, you can grill your vegetables, or lay your vegetables on a piece of aluminum foil and roast them in a smoker for about an hour.
You can combine all of the ingredients in a food processor (after peeling the garlic) and give it a few quick blitzes to leave it rough chopped, or combine until smooth (if desired). If using a mortar and pestle, combine the roasted vegetables after peeling the skin off of the tomatoes and garlic. Grind the vegetables together with the coarse salt, then add rough chopped cilantro and lime juice.
Either way you make it, once combined, taste and add more lime juice or salt (as needed, to taste).
*Just a note: We frequently skip roasting the vegetables are serve this in a raw version. It is equally wonderful!https://bakeitwithlove.com/authentic-salsa-verde/