1. Preheat oven to 375 degrees. In a food processor, pulse bread until fine crumbs form (you should have about 1 cup). In a large bowl, toss breadcrumbs with cheese, parsley, and garlic; season with 1/2 teaspoon salt and 1/4 teaspoon pepper.

2. Using one hand, dip a mushroom in melted butter to coat completely; transfer to breadcrumb mixture. With other hand, stuff mushroom with filling, patting some mixture on bottom and sides. Place, stemmed sides up, on a rimmed baking sheet. Repeat until all the mushrooms are stuffed.

3. Bake until golden brown and cooked through, 20 to 25 minutes. Let cool for a few minutes before transferring to a serving dish.