Preheat your oven to 180°C (356°F). Gently wipe the mushroom caps with a damp cloth to clean. Carefully remove the stems and chop them finely, setting aside for the filling.
Heat olive oil in a skillet over medium heat. Add the chopped mushroom stems and sauté for about 3-4 minutes until they soften and release a smoky aroma.
Add the minced garlic to the skillet and cook for another minute until fragrant, stirring constantly to prevent burning.
Transfer the sautéed stems and garlic to a mixing bowl. Stir in shredded cheddar, breadcrumbs, chopped parsley, and season with salt and pepper. Mix until well combined and the filling is cohesive.
Using a small spoon, gently fill each mushroom cap with the prepared mixture, pressing lightly to pack the filling in.
Arrange the stuffed mushrooms on a baking sheet lined with parchment paper, ensuring they sit upright and are spaced evenly.
Bake in the preheated oven for 20 minutes, or until the tops are golden brown and bubbly with a slightly crispy edge.
Remove from the oven and let rest for 5 minutes to allow the filling to set. Garnish with extra chopped parsley if desired.
Serve warm, perhaps with a side of crusty bread, and enjoy the rich, earthy aroma and satisfying textures of these beautiful stuffed mushrooms.