Preheat the oven to 180°C. Spread the walnuts on a baking tray and bake for 5 minutes until lightly browned. Remove them from the oven and leave to cool, then crush coarsely.
Cook the pasta in a large saucepan of lightly salted boiling water for 10–12 minutes, or according to the packet instructions, until al dente.
Meanwhile, crumble the cheese into a saucepan. Add the cream, mix well, and heat gently for 2–3 minutes, stirring constantly, without letting it boil.
Drain the pasta, setting aside 1½ tablespoons of the cooking water. Tip the pasta into a heated serving dish. Add the reserved cooking water to the blue cheese mixture. Scoop this sauce over the pasta and stir until incorporated. Add the nuts, grind over some pepper and serve at once.