Remove stems from mushrooms and reserve. Wipe mushroom caps with a dry towel. Place caps in an oiled baking pan. Fill each mushroom cavity with Boursin spread.
Remove from heat. Stir in Parmesan cheese and panko. Season with pepper.
Top each mushroom cap with 2-3 Tbl. of filling mixture, squeeze gently with hand to form and help shape on mushroom caps. Sprinkle each with grated Parmesan cheese and a drizzle of olive oil.
Bake for 20 - 25 minutes until golden browned. Let stand for 5 minutes before serving.