Preheat oven to 375F. Spray a large baking pan with olive oil.
Prepare the mushroom caps by washing and drying the mushrooms. Remove the stems.
In a large bowl, combine the rest of the ingredients and mix well.
Stuff each mushroom cap with the stuffing mixture (you will need ~1 teaspoon to ~1 tablespoon per mushroom cap, depending on the size of the mushroom). Place on the baking pan and bake at 375F for 15 minutes, or until the cheese is melted and the mushrooms are cooked. Serve warm.