Cook the pasta in a large pot of boiling salted water according to packet instructions. Drain and return pasta to the pot to keep warm while you make the sauce.
While the pasta is cooking, heat cream, crumbled blue cheese, pepper, and the grated zest of about half a lemon (use remaining grated zest for topping) in a small saucepan or pan, stirring often. Cook for 3-5 minutes. Taste and add a pinch of salt, if necessary. Usually no additional salt is required as the cheese makes the sauce quite salty.
Add the sauce to the cooked pasta and toss to combine. Cover with a lid and let it sit for 2-3 minutes to allow the pasta to soak up some of the sauce. During this time, the sauce will thicken. Do not skip this step as the resting time makes the sauce creamy. Stir before serving.
Serve in bowls and top with more lemon zest and some grated parmesan, if using.