Portobello mushrooms are a type of edible mushroom that belongs to the species Agaricus bisporus. They are actually mature versions of the common white button mushroom and have a meaty texture and rich, earthy flavor. Portobello mushrooms have a large, flat cap with a brownish color and are often used as a meat substitute in vegetarian and vegan dishes due to their texture and flavor. They can be grilled, sautéed, roasted, or used in a variety of recipes, including burgers, salads, and pasta dishes. Portobello mushrooms are also a good source of protein, fiber, and various vitamins and minerals, making them a nutritious addition to any diet.