Creminis, also sold as baby portobellos, are just a more mature white button mushroom. They are similar in shape, maybe slightly bigger in size, but one discernable difference is their color -- creminis are a light shade of brown. Crimino is darker, firmer and more flavorful than its cousin the white button mushroom, the two can be used interchangeably. They are a mild mushroom in flavor, and make a great substitute for white buttons in your favorite recipes as they add a deeper flavor