Prepare the Mushrooms:

Preheat the oven to 375°F (190°C). Line a baking sheet with parchment paper or foil.

Clean the mushrooms with a damp cloth and remove the stems. Chop the stems finely and set them aside.

Make the Filling:

In a mixing bowl, combine the chopped mushroom stems, breadcrumbs, Parmesan cheese, parsley, garlic, cream cheese, 1 tablespoon olive oil, salt, and pepper. Mix until well combined.

Stuff the Mushrooms:

Arrange the mushroom caps on the prepared baking sheet, cavity-side up. Spoon the filling into each mushroom cap, pressing gently to pack it in. If desired, sprinkle shredded mozzarella on top.

Bake the Mushrooms:

Drizzle the remaining olive oil over the stuffed mushrooms. Bake for 20–25 minutes, or until the mushrooms are tender and the filling is golden.

Serve:

Let the mushrooms cool for a few minutes before serving. Garnish with additional parsley if desired.