Preheat oven to 375 degrees F. Spray a large baking sheet lightly with nonstick cooking spray. Rinse and de-stem the mushrooms, and set on the baking sheet.
In a medium-sized bowl, combine crabmeat, cream cheese, parsley, green onions, parmesan, and bread crumbs. Season with salt, fresh pepper, garlic powder and red pepper flakes. Stuff the mushroom caps with the mixture and top each with a pinch of parmesan cheese.
Bake for about 20 minutes, or until the filling is hot and melted.