Preheat oven to 375°F (190°C).
Gently clean the mushrooms with a damp paper towel. Remove the stems and finely chop the stems.
In a bowl, combine the chopped mushroom stems, minced garlic, parmesan cheese, breadcrumbs, melted butter, olive oil, parsley, salt, and pepper. Mix thoroughly.
Spoon the filling generously into each mushroom cap, mounding slightly.
Place the stuffed mushrooms on a baking sheet brushed with olive oil.
Bake for 20-25 minutes, or until the mushrooms are tender and the topping is golden brown and crispy.
Garnish with freshly chopped parsley before serving.