Vegetable stock can be made any time and kept in the fridge or freezer.
Heat the oil in a saucepan, then add the vegetables, which should be peeled and sliced, as appropriate.
As they begin to colour pour on 2 pints (1.2 litres) of water. Bring to the boil and then simmer for 40 minutes until reduced by half. Strain into a jug.
Heat the olive oil in a saucepan, and gently sweat the chopped onion for 3 minutes. Add the rice and continue to cook, without colouring, for a further 3 minutes. Season with salt and pepper and then pour on the white wine, which will boil immediately.
Let this wine reduce completely, about 5 minutes, and then add half the vegetable stock and the saffron, and re-boil. Take the pan off the heat and leave it until you are ready to complete the dish. As the rice cools it will continue to cook and absorb all the liquid.
About 10 minutes before you are ready to eat, when you start to cook the vegetables, pour the rest of the stock on to the rice. Bring back to the boil, and add butter and 1oz (25g) grated Parmesan. Simmer on, and the risotto will be perfectly cooked when the stock has been absorbed.
Put the prepared vegetables into the steamer in the order of time they take to cook – carrots, courgettes, then beans and lastly mange-touts. If you have no steamer and boil the vegetables, be sure the water is boiling before starting to cook.
Spoon risotto on to each heated plate. Scatter the steamed vegetables on top, and decorate with a few shavings of fresh Parmesan.