Trim the top and bottom of the fennel, removing any discoloured pieces. Chop and reserve the feathery top. Cut the fennel in half lengthways and slice, then blanch in boiling salted water with a squeeze of lemon juice for 2 minutes. Drain and reserve liquid. Melt half the butter in a pan, stir in the chopped garlic and cook for 1 minute. Add the blanched fennel and a teaspoon of finely grated lemon and cook gently for three minutes. Remove from the heat and set aside.

Cook the plain and green pasta separately in boiling salted water until al dente. Drain and turn into a hot serving dish.

Return the fennel to the pan, add the remaining butter and the cream and bring almost to the boil. Stir in the basil and the reserved finely chopped fennel leaves. Season to taste with salt, nutmeg and lemon juice and spoon over the pasta. Toss gently with one third of the grated parmesan and, if necessary, add a little of the hot fennel liquor until the sauce coats the pasta nicely. Garnish with basil leaves and pine nuts. Serve immediately with the remaining parmesan on the side for your guests to sprinkle on to taste.