Start by cleaning the portobello mushrooms. Gently wipe them with a damp cloth or paper towel to remove any dirt. Be careful not to soak them as mushrooms can become too wet and won't crisp up.

If desired, remove the stems. You can also scoop out the gills for a less earthy taste, but it's optional.

In a bowl, mix together olive oil, minced garlic, balsamic vinegar (if using), salt, pepper, and any herbs of your choice.

Brush this mixture over both sides of the mushroom caps, ensuring they're well-coated.

It's always a good practice to preheat your air fryer. Set it to 375°F (190°C) and let it warm up for about 3 minutes.

Place the marinated portobello mushrooms cap-side down in the air fryer basket. Make sure they are not overlapping.

Cook at 375°F (190°C) for 10-12 minutes, turning them halfway through for even cooking. The exact time might vary based on the size of the mushrooms and the specific air fryer model, so keep an eye on them.

Once they're cooked to your preference, carefully remove them from the air fryer.

Serve immediately while they're hot and enjoy!