Preheat the oven to 350°F. Lightly grease a baking dish large enough to hold the mushrooms in a single layer.
Clean the mushrooms by wiping with a dry paper towel to remove any debris. Do not wash the mushrooms under water, they will absorb the water and become mushy. Remove the stems (save and use in an omelet or other dish).
In a bowl, combine all of the filling ingredients and mix well until fully combined.
Add 1-2 spoons of the stuffing into each mushroom cap and place in the baking dish.
Drizzle the melted butter over each mushroom. Cover the baking dish with foil.
Place the baking dish in the oven and bake at 350°F for 20-30 minutes or until the mushrooms are tender (or Air Fry approximately 10 minutes at 400°F).
Remove the foil from the baking dish. Sprinkle each mushroom with Mozzarella cheese. Return to the oven, uncovered, and bake until the cheese is melted.
Garnish the mushrooms with the parsley and parmesan cheese and serve.