1. Preheat oven to 375°F (190°C). 2. Remove stems from 200g portobello mushrooms and scrape out gills with a spoon. 3. Brush mushroom caps with 5ml olive oil and 5ml balsamic vinegar. Place on a baking sheet and roast for 10 minutes. 4. Meanwhile, heat 5ml olive oil in a skillet over medium heat. 5. Add 50g diced onion and cook until translucent, about 3 minutes. 6. Add 6g minced garlic and cook for 30 seconds. 7. Add 50g diced bell pepper and cook for 3 minutes. 8. Add 60g spinach and cook until wilted, about 2 minutes. 9. Add 100g cooked brown lentils, 2g Italian seasoning, 1g salt, and 1g black pepper. Cook for 2 minutes. 10. Remove from heat and stir in 15g breadcrumbs and 10g grated Parmesan cheese. 11. Fill the mushroom caps with the lentil mixture. 12. Sprinkle with 30g shredded mozzarella cheese and remaining 5g breadcrumbs and 5g Parmesan cheese. 13. Bake for 15-20 minutes until cheese is melted and golden. 14. Garnish with 5g chopped parsley before serving.