Preheat oven to 400F. Grease a 9x11 inch baking pan, or spray it with non-stick spray.
Clean the mushrooms, and remove the stems. Save the stems!!Finely mince about half the mushroom stems - they will go into the stuffing. You can use a garlic press to press them right into the bowl where you will make the stuffing.
In a large bowl, combine the shredded cheese, breadcrumbs, minced herbs, minced garlic cloves, and olive oil. Mix well. Add salt and pepper if necessary (Salt is optional, since the cheese and Italian breadcrumbs contain salt).
Stuff each mushroom cap with 1-2 tablespoons of stuffing, really pack it in there with your hands to make sure the stuffing doesn't fall out.Arrange the mushrooms in the baking pan, and bake at 400F for 17-19 minutes, or until the mushrooms are cooked and the stuffing is melted and starting to turn golden on top.