These Air-Fryer Portobello Melts are a delicious vegetarian option for a quick and easy meal. Portobello mushrooms are marinated in a flavorful balsamic glaze, then topped with melted cheese and roasted red peppers. The mushrooms are cooked in an air fryer until tender and juicy, with a crispy exterior. Serve these melts on toasted buns for a satisfying and flavorful sandwich.