Clean and trim the mushrooms, set aside.
Whisk together the egg and buttermilk.
Combine the flour, breadcrumbs, salt, garlic salt, Italian seasoning, and pepper.
Dip each mushroom into the flour mixture, then the buttermilk, then back into the flour again.
Coat the basket of the air fryer with grapeseed oil spray.
Place the mushrooms evenly into the air fryer.
Coat the mushrooms with grapeseed oil spray.
Cook in the Air Fryer at 390*F for 15-20 minutes until they are golden brown. (Note - This is in a cold air fryer, it is not preheated. Be sure to check in on them around 10 minutes since all air fryers heat differently.)
If they appear floury, coat again with grapeseed oil spray.
Serve with ranch dressing or marinara for dipping and garnish with dried parsley.