SAN DIEGO--(BUSINESS WIRE)--Brace yourselves for a savory sequel! Jack in the Box® announced today the launch of the NEW Portobello Mushroom BUTTERY JACK™. This mouthwatering burger is the newest craveable offering from the popular BUTTERY JACK line and features flavorful Portobello mushrooms, creamy peppercorn mayo, grilled onions, Swiss cheese and melted garlic herb butter atop a quarter-pound signature beef patty, served on Jack’s gourmet signature bun. The Portobello Mushroom BUTTERY JACK j