While the pasta is cooking, simmer 2 cups of heavy cream in a big skillet. When cream is reduced by about a third, throw in the zest of two lemons, and a couple of tablespoons of fresh chopped rosemary leaves.
Cook a few more minutes, then transfer drained pasta to the skillet and toss with the sauce.
Add salt, lots of fresh ground pepper, and plenty of pecorino romano. Ready to serve!