Arrange garlic cloves on baking sheet and place under broiler until toasted. Keep an eye on them and don't overcook to avoid a burned and bitter flavor.
Remove the toasted garlic to a small bowl and set aside.
Place peppers, tomatillos(can be halved), and onion on baking sheet. Place under broiler until nicely charred, turning to cook evenly. Set aside to cool. Do not remove charred bits!
Place all broiled ingredients in blender or food processor with lime juice, salt, cumin, and blend. Refrigerate before serving to allow flavors to blend.