Boil a large pot filled with water. Peel the pear, remove the core and cut into cubes. Melt the butter in a pan, add the pears and cook over high heat for a few minutes. Meanwhile, chop the gorgonzola into cubes and walnuts. Throw the pasta in boiling salted water. Pour the cheese cubes into the pan with the pears and let them melt, adding a dash of milk. When the pasta is cooked, pour into the pan, stir well and add some of the walnuts. Garnish the pasta with the remaining walnuts and a sprinkling of pepper. Serve hot.