Heat the oil in a large saucepan or casserole pot over a medium low heat. Add the celery, onion, carrot, garlic, salt and pepper, and cook gently for 15 minutes, stirring occasionally, until the vegetables are tender.
Add the mushrooms and courgette, increase the heat to medium and cook for 5 minutes, stirring occasionally, until any liquid has evaporated.
Stir in the tomatoes, tomato purée, herbs, lentils and balsamic vinegar. Pour in the wine, bring to the boil and cook for 1 minute.
Add the vegetable stock, bring back to the boil then turn the heat down and simmer, uncovered, for 20 to 25 minutes, until the lentils are tender. Remove and discard the bay leaf, taste and check the seasoning, adding more if needed.
With 10 minutes to go on the bolognese, cook your choice of pasta according to the packet instructions, drain and serve with the bolognese. Garnish with the grated parmesan cheese and extra basil leaves, if you like.