Heat a dry non-stick frying pan and, when hot, fry the pancetta until browned and crisp. Drain and set aside. Heat the stock to a gentle simmer in a saucepan.
In a large saucepan, gently saute the shallots and pumpkin in the oil for about 5 minutes. Stir in the rice and cook for a further 2 minutes to toast the grains. Pour in the wine and cook until reduced right down.
Now pour in one-fourth of the stock and stir well. Cook gently until the liquid has been absorbed, then stir in another ladleful of stock. Continue cooking and stirring, gradually adding the stock, until the rice grains are just tender and the risotto is creamy. The whole process should take about 15 minutes.
About 2 minutes before the end of cooking, stir in the pancetta, mascarpone, and half the Parmesan. Check the seasoning, then serve in warm bowls, sprinkled with the remaining Parmesan.
Recipe courtesy Gordon Ramsay's A Chef for All Seasons