Preheat your oven to 375°F (190°C). Clean the mushrooms with a damp cloth and remove the stems, chopping them finely.

In a skillet, heat 1 tbsp of olive oil. Add chopped mushroom stems, onion, and garlic. Sauté for about 5 minutes until soft.

In a mixing bowl, combine sautéed mixture with breadcrumbs, Parmesan cheese, parsley, thyme, salt, pepper, and remaining olive oil. Mix until well blended.

Stuff each mushroom cap with the filling, packing it tightly. Arrange on a lined baking sheet.

Bake for 18 to 20 minutes until mushrooms are tender and tops are browned.

Let cool slightly, garnish if desired, and serve warm.