Preheat your oven to 180°C (350°F) and line a baking sheet with parchment paper or a silicone mat.
Gently clean each mushroom cap with a damp cloth to remove any dirt. Remove the stems if they seem too thick, but keep them if you want extra flavor in the stuffing.
In a small bowl, combine the olive oil, minced garlic, chopped thyme, salt, and pepper. Mix well until fragrant and evenly blended.
Using a brush or your fingers, lightly coat each mushroom cap on all sides with the oil mixture. This helps infuse flavor and keeps them moist as they bake.
In a small bowl, stir together breadcrumbs and grated Parmesan cheese. Drizzle a teaspoon of olive oil over the mixture and toss gently to coat, adding a bit more if it seems dry.
Stuff each mushroom cap generously with the breadcrumb mixture, pressing down lightly to pack the filling and mound it slightly over the top for a rustic look.
Arrange the filled mushroom caps on the prepared baking sheet, placing them cap side up and spacing them evenly.
Bake in the preheated oven for 20–25 minutes, until the tops are golden brown and crispy, and the mushrooms are tender to the touch.
Remove from the oven and let rest for 5 minutes. The aroma should be rich and mushroomy, with a crispy, browned topping.
Serve warm, garnished with a sprinkle of fresh herbs if desired. Enjoy the smoky, tender bites that bring out the best in these humble fungi.
