The fundamental cheeses that go into pesto are Parmesan and Sardinian pecorino. For a lighter taste impact, Genoese cooks sometimes thin the consistency by adding ricotta, as I have described on pages 190-1 in More Classic Italian Cooking. In the following recipe I have gone a little farther and substituted goat cheese for all other cheeses. It makes a more loosely knit pesto, one with notable freshness and tang. This, like all sauces derived from basic pesto (please see The Classic Italian Cook Book, pages 139-42), is a condiment that must be used raw, without undergoing any cooking, no matter how brief.