Preheat oven to 425 degrees Fahrenheit. Clean the mushroom caps by wiping with a damp paper towel and setting on a sheet pan covered with parchment paper. Carefully twist and pull out the stems and either discard or use them for another recipe.

Take 2-3 teaspoons of Boursin cheese and fill the mushroom cap till completely full. Place back on the baking sheet and bake at 425F for 15 minutes. For smaller mushrooms, bake 12-13 minutes and 15-16 minutes for very large mushrooms. Cheese should be light brown on top and caps should be softened.

Remove the mushroom caps and place on a serving plate. Sprinkle with parsley and freshly cracked black pepper. Taste and add salt if needed.