Melt 25g of butter with the olive oil in a large heavy based saucepan, then add the finely chopped onion and cook over a gentle heat until soft.

In the meantime bring the stock to the boil in a saucepan.

Add the rice to the onion, stirring it for a couple of minutes until it looks nice and glossy. Add the wine and stir until it has completely evaporated. Then start adding a ladle of stock at a time stirring continuously.

Every time the stock has been absorbed by the rice, add another ladleful. It should take about 20-25 minutes. It should be soft and a bit creamy but each grain should have a little bit in the centre (al dente).

When almost ready I normally add the sachet of saffron and keep stirring. Some people melt the saffron in the broth at the beginning, it's up to you. I then add the rest of the butter and stir. Some people add a little extra thick double cream but this is not in the original version.

Let it rest for a couple of minutes, then serve it with Parmesan cheese on top.