Peel the skin off of your mushroom caps. Halve them down the middle.
In a large bowl, mix to combine the olive oil, parmesan and spices. Add the mushroom halves to the bowl and mix to coat. If they seem a lilttle dry, add a little more olive oil and mix.
Dip the cut side into the freshly grated parmesan and place them cut side down onto a large baking sheet. Bake for 17-20 minutes or until golden on the bottom. Time varies with size of mushrooms. Top with more chili flakes and freshly grated parm and serve.