Preheat the oven to 425 degrees. Place the tomatillos on a small baking sheet and into the oven. Roast until they turning brown and starting to deflate, about 12 minutes. Remove from the oven and allow to cool. Roughly chop the tomatillos.
In a large bowl, combine the onions, peppers (if you like your guacamole really spicy, feel free to leave in the seeds of one or both the jalapeno peppers), chopped tomatillos, and the avocadoes. Using a potato masher or a large fork, mash to a chunky puree. Squeeze in the lime and add the salt and pepper. Either continue to mash (for a smoother consistency) or use a spatula to mix well. Taste and adjust seasoning as necessary.
Recipe by In Good Taste at https://ingoodtaste.kitchen/roasted-tomatillo-guacamole/