Preheat the oven to 375°F (190°C).
Clean the mushroom caps with a damp cloth and remove stems. Gently scoop out gills if desired.
In a bowl, mix goat cheese, breadcrumbs, parsley, garlic, salt, and pepper until well combined.
Brush the mushroom caps lightly with olive oil.
Divide the cheese mixture evenly among the mushroom caps, pressing gently to pack it in.
Place stuffed mushrooms on a baking sheet lined with parchment paper.
Bake for 20-25 minutes, or until the mushrooms are tender and the filling is golden brown.
Let cool for 5 minutes. Drizzle with balsamic glaze if desired and serve warm.