This pasta dish is modeled on the spaghetti al pesto di limone that Giovanna Aceto made for us on her family’s farm in Amalfi, Italy. The lemons commonly available in the U.S. are more acidic than Amalfi’s lemons, so to make a lemon pesto that approximates the original, we use a little sugar to temper the flavor. For extra citrus complexity, we add lemon zest to the pasta cooking water; the oils from the zest lightly perfume the spaghetti, reinforcing the lemony notes of the pesto.

Don’t forget to remove the lemon zest from the boiling water before dropping in the pasta. If left in as the spaghetti cooks, the zest may turn the water bitter, and the strips are a nuisance to remove from the strands of cooked noodles.