Vegetable and lentil pot pies

Name: Vegetable and lentil pot pies
Prep time: 25 min
Cook time: 50 min
Total time: 1 h 15 min
Cuisine: European, British
Ingredients: 1 tablespoon olive oil; 1 medium onion (150g), chopped finely; 1 medium carrot (120g), chopped coarsely; 2 stalks celery (300g), trimmed, chopped coarsely; 1 medium parsnip (250g), chopped coarsely; 2 cloves garlic, crushed; 200 grams button mushrooms, sliced thickly; 2 bay leaves; 1 tablespoon finely chopped fresh rosemary, plus extra leaves to serve; ¼ cup (70g) tomato paste; 1 cup (250ml) vegetable stock; 400 gram can diced tomatoes; 150 grams green beans, trimmed, chopped coarsely; 2 x 400g cans brown lentils, drained, rinsed; 300 grams potatoes, chopped coarsely; 300 grams orange sweet potato, chopped coarsely; 60 grams butter; ½ cup (40g) finely grated parmesan-style cheese