Bring a large pot of lightly salted water to a rolling boil. Cook penne in the boiling water, stirring occasionally, until tender yet firm to the bite, about 11 minutes; drain.

Return drained pasta to the pot; stir butter, Parmesan cheese, and Gorgonzola cheese into pasta and place over medium heat; cook until the cheese is completely melted. Pour cream into pasta mixture; stir. Remove from heat and fold in pear. Top with walnuts. Season with pepper and serve.