Spaghetti with Creamy Basil Pesto

The first basil pesto recipe is thought to be from the mid-eighteenth century, though the word pesto implies any sauce that is pestato, or mashed, traditionally in a marble mortar and pestle. Its origins may be from the Orient, where sauces of pine nuts and cheese mashed together were the custom. The most common version is with Parmigiano-Reggiano and aged pecorino cheese, as in the previous recipe. A lesser-known traditional recipe has no pecorino but instead uses a cheese cu