Preheat the oven to 350 degrees F and spray a baking dish large enough to hold the mushrooms with a non-stick cooking spray.
Remove the stems off the mushrooms and clean the mushrooms with a dry paper towel (due not use water or it will make the mushrooms soggy).
Stir together all the filling ingredients in a mixing bowl.
Add 1-2 spoons of the filling into each mushroom cap and place it filling side up on the baking dish (you should be able to stuff 8-12 mushrooms based on the size of your mushrooms).
Then drizzle 3 Tbsp of melted butter over the prepared mushrooms.
Cover the baking dish with foil and bake for 20-30 minutes until the mushrooms are tender.
Remove the foil and sprinkle the top of each mushroom with the grated mozzarella cheese. Bake (uncovered) for 2-3 minutes until the cheese is melted.
Then the mushrooms are ready to serve and enjoy!
Notes
These are best served fresh but you can refrigerate the leftovers for up to 3 days. Reheat in the oven or air fryer to make them heated through and slightly crispy again.