Preheat the broiler. Cut the tomatillos in half. Place them face down in an oven-safe baking dish. Place the dish 5” from the broiler. Broil for 7 minutes, flip the tomatillos, and broil for 7 more minutes. Let the tomatillos cool for 5 minutes. Add the tomatillos and all remaining ingredients to a food processor bowl. Pulse for 15 seconds or until smooth.
3 tomatillos, ¼ white onion, 3 cloves garlic, 2 chipotle peppers in adobo sauce, 2 tablespoons chopped cilantro, 1 teaspoon ground black pepper, 1 teaspoon A1 steak sauce, 1½ limes