Preheat the oven to 375°F (190°C).
Remove the stems from the Portobello mushrooms and scrape out the gills using a spoon.
In a skillet, cook the ground turkey, onion, bell pepper, and garlic over medium heat until the turkey is no longer pink.
Stir in the parsley, oregano, basil, salt, and black pepper.
Place the Portobello mushrooms cap-side down on a baking sheet and fill each mushroom cap with the turkey mixture.
Top each mushroom with shredded mozzarella cheese.
Bake in the preheated oven for 20-25 minutes, or until the mushrooms are tender and the cheese is melted and golden brown.
Serve hot and enjoy!