Bring a large pot of water to a boil. Add salt, keeping in mind the anchovies are salty. Add the spaghetti to the boiling water.

Meanwhile, in a skillet, melt the butter with a small drizzle of extra-virgin olive oil (the oil has a higher smoke point than butter and helps prevent the butter from burning).

Add the anchovy fillets and use a wooden spoon to mash them until they dissolve, adding a ladleful of pasta cooking water.

Add a light grating of lemon zest, then add the al dente spaghetti to the skillet.

Toss the pasta with the cooking water until fully cooked.

Turn off the heat, add the juice of half a lemon, and continue tossing the pasta off the heat.

Serve with a generous grating of lemon zest on top. Enjoy!