In a cast-iron skillet, heat 1 tablespoon of olive oil. Add onion and cook 2-3 minutes until translucent. Add garlic and sauté an additional one minute. Add remaining vegetables, steak seasoning and dried parsley. Sauté vegetables for about 5 minutes or until peppers are softened. Stir in cream cheese and mozzarella cheese and combine with vegetable mixture until completely melted. Slice open sweet potatoes and fill each with 1/3 of mixture. Top with more parsley and enjoy!