For a vegetarian twist on the classic hamburger, try this portobello mushroom recipe in the air fryer. Remove the stems from portobello mushrooms and season with salt, pepper, and olive oil. Cook in the air fryer at 375°F for about 8-10 minutes. Meanwhile, toast the buns in the air fryer for a few minutes. Assemble the hamburger by placing the portobello mushroom on the bun and topping with your favorite condiments and veggies. Enjoy a meatless and flavorful hamburger alternative!