Melt half the butter with the oil in a large saucepan, add the garlic and onion and fry gently for 5 minutes.
Add the rice and stir well to coat each grain with the butter and oil. Add enough stock to just cover the rice and stir well. Simmer gently, stirring frequently.
When most of the liquid is absorbed, add more stock and stir well. Continue adding the stock a little at a time, stirring until it is absorbed and the rice is tender but retaining a little bite – this will take about 25 minutes. You may not need all the stock. Add the vegetables and vermouth or wine, mix well and cook for 2 minutes.
Remove the pan from the heat, season and add the remaining butter, the parsley and the Parmesan. Mix well and serve.