Finely chop the onion and leek. Chop the radicchio into small pieces. Bring the stock to the boil and keep just below simmering point.
2
Heat the oil and butter in a medium saucepan. Add the onion and leek and cook until softened. Add the radicchio and stir until coated with butter.
3
Now add the rice and coat in butter, stirring well.
4
Add a ladle of stock and cook until the liquid has been absorbed. Continue adding the stock, stirring between each addition until the rice is tender but firm. This will take 20-30 minutes.
5
Add the parmesan cheese, sugar and season with salt and pepper to taste.