Beef Brisket with Chipotle Tomatillo Sauce

Place the tomatillos, chipotle peppers, tomato sauce, water, salt, and brown sugar in the work bowl of a food processor, and blend until smooth. Set the mixture aside.

Heat the olive oil in a pressure cooker with the lid off over medium heat, and cook and stir the onion and garlic until the onions are translucent, about 3 minutes. Drop the brisket into the pressure cooker, and sear it on both sides. Pour the tomatillo mixture over the brisket, bring to a boil, and place the lid on the cooker. When the pressure comes up, set the heat so the cooker develops medium pressure, and cook for 1 hour and 15 minutes.

Allow the cooker to release pressure on its own (without using the quick-release), and remove the brisket. Serve hot, with tomatillo sauce on the side.