Step 1

Bring a large pot of water to a boil over high heat. Season generously with salt. Add the pasta and cook until just al dente, about 9 minutes.

Step 2

Meanwhile, heat a large skillet over medium heat. Add the butter to the pan and warm  until it melts. Add the anchovy filets and cook, breaking them apart with the back of a wooden spoon, until they are practically dissolved in the butter, about 4 minutes. They should look like little unidentifiable specks in the butter and should smell nutty. If some of the butter browns as well, that is just fine. Using tongs, remove the pasta directly from the pasta water into the pan with the anchovy butter. Add the lemon zest, juice and 1/2 cup of pasta water. Start tossing over medium heat, until a light creamy sauce forms and clings to the pasta. Stir in the parsley and serve.