First place the saffron threads in a small bowl and cover with the water. Cover and leave to infuse for at least 6 hours.
Bring the stock to the boil in a pan. Then switch off the hob.
Peel and finely chop the shallots.
Heat the olive oil in a large pan and sauté the shallots in it. As soon as they are translucent, add the rice and sauté for 1-2 minutes.
Pour in the wine and simmer until it has evaporated.
Add a ladle of stock to the risotto and wait until the liquid has been absorbed before adding the next ladle of stock. Stir well all the time. Gradually add all the stock in this way.
When the rice is almost cooked, add the saffron and infusion. Stir well and finish cooking the rice, adding salt if necessary.
When the rice grains are al dente, remove the risotto from the heat and stir in the grated Parmesan and butter to make the rice creamy and glossy.