Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper.
Clean the mushrooms by wiping them with a damp paper towel. Remove the stems and scoop out the gills for extra filling space.
In a bowl, combine breadcrumbs, Parmesan cheese, minced garlic, parsley, oregano, salt, and pepper. Mix well.
Brush the mushroom caps with olive oil on both sides. Place them cap-side down on the prepared baking sheet.
Divide the breadcrumb mixture evenly among the mushrooms, packing it gently into the caps.
Bake for 18–20 minutes, or until the topping is golden brown and the mushrooms are tender.
Serve warm, garnished with additional parsley if desired.