Finely chop the shallots, celery and the carrot, then heat with the oil and half the butter in a large saucepan, and cook to soften for about 3 minutes.

Finely chop the shallots, celery and the carrot, then heat with the oil and half the butter in a large saucepan, and cook to soften for about 3 minutes. Mix in the rice, stirring to give it a good coating of oil and butter. Meanwhile, heat the stock in another saucepan and keep it at simmering point. Stir into the rice a ladleful of the simmering stock and cook over moderate heat, stirring continuously. When the stock has been absorbed, stir in another ladleful. Continue like this for 20 minutes, until all the stock has been added and the rice is al dente. You may not use all the stock, or you may need a little extra; every risotto will be slightly different.

Mix the lemon zest and rosemary into the risotto, and in a small bowl beat the lemon juice, Parmesan, cream and pepper. When the risotto is ready, the rice is no longer chalky but still has some bite, take it off the heat and add the bowl of lemony mixture, and the remaining butter and salt to taste. Serve at once with more grated Parmesan if you wish.