1. Lightly clean off mushrooms with a damp cloth. Trim off any stems. Preheat oven to 425 degrees F.

2. Brush each mushroom with olive oil. Place on baking sheet in single layer. Bake for 5 minutes, turn over and bake another 5 minutes. Remove from oven and set aside. Reduce oven temp to 400 degrees F and leave on.

3. In mixing bowl, combine tomatoes, breadcrumbs, Parmesan, parsley and egg. Sprinkle with salt and pepper.

4. After it is well blended, scoop some mixture into each mushroom cap. Overfilling is ok. Bake for about 15 minutes or until mushrooms are soften and stuffing is lightly browned.

5. Remove from oven, top each mushroom with a slice of mozzarella cheese. Return to oven for 3-5 minutes to melt the mozzarella. Optional: drizzle a little extra virgin olive oil and sprinkle with extra parsley before serving. You can experiment with different ingredients for stuffing the Portobellos, such as adding some finely chopped onions and shredded carrots, or chopped basil. All these would pair well with the other ingredients. Serve as a delicious appetizer and enjoy!