Basil is abundant in summer's last gasp, and if you are looking for a way to preserve it, then making a large batch of pesto and freezing the extra is a great way to extend this rich, summery flavor into the start of chilly autumn days.
The pesto that most of the world knows as the one-and-only "pesto" is, in fact, just one of endless kinds. "Pesto" means "pounded," from the verb pestare ("to pound"), because the old-fashioned way to make pesto (and the one that many cooks still swear by) is to pound the ingredients -- a mixture of aromatic herbs, salt, garlic, olive oil, cheese, and sometimes nuts -- with a mortar and pestle to form a paste, which could then be thinned with some water, vinegar, broth or verjuice to form a sauce. And not just a sauce for pasta, but for all kinds of foods. The origins for such a condiment date back at least as far as the ancient Romans, who made a pesto called moretum to eat with bread.
The most famous of all pestos, Genoese-style pesto, originates from the coastal region of Liguria, where traditionally this fresh-basil pesto is made with a mixture of Parmigiano-Reggiano cheese and Pecorino, and eaten with either dried trenette (a long, thin, flattish pasta similar to tagliatelle) or fresh trofie, a short, chewy twisted pasta -- with chopped potatoes and green beans cooked together with the pasta and all tossed together with the pesto sauce.
Naturally, as with any classic Italian recipe, there are probably as many versions as there are cooks, but I personally prefer a half-half mixture of Parmigiano and Pecorino for the nice balance that gives between the tangy-tart Parmigiano and the salty, pungent Pecorino.
With such a simple, uncooked sauce, it's of course important to use the freshest and highest-quality ingredients possible -- a very good, extra-virgin olive oil, good pine nuts (avoid short, round, dark-tipped pine nuts from the Chinese species pinus armandii, which can cause the short-lived, but distressing, "pine mouth" syndrome, which can leave a bitter, metallic taste in your mouth for up to two weeks, and look for longer, thinner, evenly-colored pine nuts, such as American-grown and Italian-grown varieties, which do not cause "pine mouth"), genuine Parmigiano-Reggiano (see this article for tips on how to spot the real deal) and Pecorino, and fresh garlic.
As for equipment, I do not belong to the "mortar and pestle or die" camp of pesto-makers. I have tried making pesto in a mortar and pestle, with a mezzaluna, with a food processor, and with a handheld immersion blender, and I prefer the latter two methods. The mortar-and-pestle version was just too chunky for my taste. I like the way a smoother pesto emulsifies and gives a silky feel to the final dish.
- 2 cups fresh basil leaves, washed and dried thoroughly (pat them dry with a paper towel, if necessary)
- 2 tablespoons pine nuts (see notes above regarding pine nuts)
- 2 medium garlic cloves, peeled and roughly chopped
- 1/4 teaspoon fine sea salt
- 1/2 cup extra-virgin olive oil
- 1/4 cup grated Parmigiano Reggiano (a Microplane grater works very well for this, because it grates the cheese so thin that it melts instantly when it touches the hot pasta or pasta cooking water)
- 1/4 cup grated Pecorino (Romano or Sardo)
Place the basil, pine nuts, garlic, and salt in a food processor and pulse until pureed into a smooth paste.
Transfer to a small bowl and stir in the olive oil until evenly mixed.
Stir in the cheeses until mixture is homogenous.
Notes for serving: If serving on pasta, be sure to retain a ladleful of the pasta cooking water, and add a bit of the water to the cooked pasta together with the pesto sauce, to thin it, melt the cheeses and help it to adhere to the pasta.
Add just a little bit at a time. Serve with additional grated cheese at the table, if desired. I love to add halved fresh cherry tomatoes or quartered cocktail tomatoes as well, when I'm mixing the pesto sauce with the pasta.
In Liguria, pesto is traditionally served either on long, flat trenette pasta or short, twisted trofie pasta, together with potatoes and green beans that are cooked together in the pot with the pasta. This is called pesto "avvantiaggiato" (pesto with benefits) or pesto "ricco" (rich pesto).
Notes for storage: You can store pesto, topped with a thin layer of extra-virgin olive oil, in an air-tight glass container in the refrigerator for up to a week. Freeze extra pesto in ice-cube trays, then transfer the cubes of frozen pesto to a zipper-lock freezer bag for long-term freezer storage. That way, you can take out enough pesto for just one or two servings of pasta, if desired.