Preheat oven to 400°F.
Line a baking sheet with parchment paper and lightly spray with some oil. Set aside.
Clean the mushrooms, remove stems, and roughly chop stems, add to a bowl. Place mushroom caps onto the prepared baking sheet.
Add the rest of the ingredients to the bowl with the chopped stems, stir to fully combine together.
Fill each mushroom cap with the prepared stuffing.
Bake for about 15-20 minutes or until the stuffing is golden-brown.
