Turn your oven broiler on high and line a baking sheet with foil.
Arrange the tomatillos (cut side down), jalapeƱos, and garlic cloves on the foil and place about 4" under the broiler. Let cook for 4-6 minutes, or until the skins on the tomatillos are starting to blacken.
Remove from the heat and transfer (along with all juices on the foil) to a blender. Add the onion, lime juice, and cilantro. Blend until mostly smooth, and add salt & pepper to taste.
Recipe by The Kitchen Paper at http://c02.ddd.mwp.accessdomain.com/roasted-tomatillo-salsa/