Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper. Gently clean the mushroom caps with a damp cloth, then carefully remove the stems and set them aside.
Chop the mushroom stems finely and set aside. In a mixing bowl, combine the minced garlic, chopped herbs, breadcrumbs, grated parmesan, half of the olive oil, chopped stems, and a pinch of salt and pepper.
Stir everything together until the mixture is well combined and slightly sticky. If it feels dry, add a splash more olive oil.
Using a small spoon or piping bag, carefully stuff each mushroom cap with the filling, pressing gently to pack it in. Place the stuffed caps on the prepared baking sheet.
Drizzle the remaining olive oil over the stuffed mushrooms and sprinkle with shredded mozzarella if using. This helps create a bubbling, golden topping.
Bake in the preheated oven for about 20 minutes, until the tops are golden brown and bubbling, and the mushrooms are tender to the touch.
Remove from the oven and let rest for a few minutes. The filling will settle and develop a rich aroma. Garnish with extra herbs if desired.
Serve warm as an elegant appetizer or main course, enjoying the tender mushrooms with a cheesy, aromatic filling.