Preheat oven to 350 degrees F. Heat oil in a skillet set over medium high heat.
Cook mushroom on both sides until they slightly soften, and then remove and place stemmed side up on a baking sheet. Arrange slices of tomato in spiral-like fashion on top of the mushrooms. Combine stuffing ingredients, except Parmesan cheese, in a bowl. Divide and place stuffing on top of the mushrooms and tomatoes. Sprinkle on cheese.
Bake 20 minutes.