stuffed portobello mushroom recipe

Ingredients: 4 large portobello mushrooms 2 tablespoons olive oil Salt and freshly ground black pepper to taste 1 cup breadcrumbs 1/2 cup grated Parmesan cheese 1/2 cup shredded mozzarella cheese 1 small onion, finely chopped 3 cloves garlic, minced 1/4 cup sun-dried tomatoes, chopped (optional) 2 tablespoons fresh parsley, chopped