Preheat the oven to 430F/220C. Line two baking sheets with parchment paper.
Place the cleaned mushrooms on baking sheets.
Brush each of them with olive oil. Sprinkle salt, pepper and fresh rosemary leaves over them. Bake for 25 minutes or until brown and crispy. The baking duration might be different depending on the size of your mushrooms and your oven. So keep an eye on them and check after 10 minutes.
Serve immediately.
In the air fryer:
Preheat air fryer to 360F/180C for about
Prepare the mushrooms as described above.
Spritz the fryer basket with oil or cooking spray. Place oyster mushrooms into the basket in a single layer.
Spritz the mushrooms with oil. Sprinkle salt, pepper and rosemary leaves.
Cook for 5 minutes, flip them over and cook for another 5 minutes or until crispy and golden brown.
NOTES
The mushrooms shouldn’t overlap when you place them on the baking sheet to roast them in oven, so I used two baking sheets.