Heat the oil and butter in a large pan. Add the onion and fry gently until softened. Add the garlic and fry for 2 minutes.
Add the risotto rice and stir to coat. Add the tomatoes and your first ladle of vegetable stock.
Add the remaining stock slowly as each ladle is absorbed. Stir well to reach the creamy texture desired.
When you have just one more ladle of stock left, add your grated courgette along with the last of the stock. If you are adding sun blush tomatoes or slow roasted, also do so now.
When the stock has all been absorbed and the risotto is wonderful and oozy, add a good handful of Parmesan cheese and season to taste. Let your risotto rest for 2 minutes before serving scattered with more Parmesan cheese.