Drizzle a little olive oil into a baking dish and place the mushroom caps in the dish with the cavity facing upwards.
2.
Heat 4 Tablespoons of olive oil in a frying pan over medium heat.
Place the mushroom stems, onion, and garlic in the pan and cook until slightly browned.
Remove from heat.
3.
Mix bread crumbs, cheese, parsley, salt, red pepper flakes, and oregano in a separate bowl.
4.
Stir the onion, garlic mixture into the dry mixture.
Fill the cavities of the mushroom caps with the breading.
5.
Drizzle a bit of olive oil over the tops of the mushroom (if you have some extra cheese, you could sprinkle some on now as well) and bake at 400 degrees F for 15-20 minutes (until slightly browned).