Preheat the oven to 400 degrees F.
Stir the breadcrumbs, parmesan cheese, garlic, parsley, mint, salt and pepper, and 2 Tbsp of the olive oil in a medium bowl to blend.
Drizzle a heavy large baking sheet with about 1 Tbsp olive oil, to coat. Spoon the filling into the mushroom cavities and arrange on the baking sheet, cavity side up. Drizzle remaining oil over the filling in each mushroom. Bake until the mushrooms are tender and the filling is heated though and golden on top, about 25 minutes. Serve warm.