Pesto Genovese, a combination of basil, olive oil, garlic, pine nuts or almonds, butter, and cheese, is justly famous as a sauce for pasta. Not many people know that Genoa’s pesto throne is contested, with Trapani in Sicily offering a rival version with tomatoes.

In fact, if your enthusiasm for pesto rests on the marvelous combination of fresh basil and garlic, you may not want a pesto at all, but a simple pistou, which is those two ingredients alone.

For any of the recipes below - pistou with olive oil, tomato pestos, or pesto Genovese, a few notes on preparation are in order.

The Food Processor

Many Genoese say that mortar and pestle are necessary for true pesto. But even the Italian authorities Adi Boni and Marcella Hazan, as well as the careful researcher Carol Field, say that the food processor works very well.

The Garlic Press

Even though the authorities do not say so, I believe that the garlic should be pureed, not chopped in the food processor.

This is the method customarily recommended by Julia Child when garlic is to be added and eaten raw. There is a good reason. In the pureed, or semi-liquid state, the garlic will go quite quickly and uniformly into the basil and oil. The need for mashing the garlic, rather than chopping it, is probably the main reason that some Italians insist on mortar and pestle.

If you do not have a hand-held garlic press, you really should peel the garlic, mash it, mince, mash again. You can see why the press is so desirable, as not even peeling is necessary.

The only disadvantage of the press comes in the cleaning. This is easiest if you use a toothpick to poke the garlic back through the holes, then flush back with a stream of water, a small price to pay for the overall convenience and control of flavor.

Refrigeration and freezing

Pestos can be refrigerated for a day or two and can be frozen 2 or 3 months. Except for the garlic, the flavors improve with adsorption.

In my experience, the garlic loses its fresh flavor when either refrigerated or frozen. I therefore do not add any garlic until just before serving. This is easily done using pureed garlic from a hand held press.

Pistou in its basic form is simply a mixture of basil and garlic. It began as an addition for soups, later extended, with embellishments, to such as beef stews and eggplant dishes. Pistou is always added at the end, never during cooking, to preserve the fresh basil flavor.

Pistou was not a parallel invention of the French, but originated on the French Riviera by Genoese sailors who sought reminders of home (Waverly Root, The Food of Italy).

The mixture of basil and garlic alone will not coat pasta. So in our modern kitchen, if your intent is an American-style pasta sauce, you need to add a little olive oil.

Serves 4 to 6 for 1 ¼ pounds pasta

To make the pistou, shred basil in the food processor. Puree the garlic and add some to the processor. Whip and taste and add more if desired. That is pistou, to be used as a flavoring for soup or other dishes.

To make a pasta sauce, add a little olive oil and whip a minute in the food processor. Stir in more olive oil to reach the desired consistency.

Since tomatoes go so well with basil, why not a tomato pesto? This question was apparently not asked in Genoa, but it was in Trapani in Sicily, where the butter and cheese of classic pesto were replaced by tomatoes.

If you have fresh, ripe tomatoes in season, you can make the Pesto alla Trapaneze below. The rest of the year use plum tomatoes, first making a tomato coulis from them. The coulis makes a fully competitive pesto, with concentrated, surprisingly fresh tomato flavor.

Makes 1 cup

To make the tomato coulis

Peel the tomatoes for more concentrated flavor. (Film the bottom of a pan with water. Cover and bring to simmer. Simmer tomatoes until skin is loosened, about 45 seconds to 2 minutes, depending on tomato.)

Pour water from the pan. Cut tomatoes through the equator and remove seeds.. Chop the tomatoes in ¼ inch pieces and place them in the pan. Bring rapidly to the simmer. Simmer briskly uncovered, stirring constantly.

After a minute or two tomatoes will become soft. Mash them with a fork or potato masher. Continue the brisk simmer until most of the free moisture is gone.

To make the pesto

Whip almonds in the food processor until they are almost a flour.
Add basil, tomato coulis, and olive oil. Whip until blended into a paste.
Puree the garlic in the hand press. Add some garlic to the mixture. Whip, taste, and add more as desired.
Season to taste with salt and pepper.

For this recipe, fresh summer tomatoes are a must. Plum tomatoes, uncooked, do not have enough tomato flavor.

In addition to use of fresh tomatoes, this follows the original recipe, blanching the almonds. Red pepper flakes and Italian flat-leaf parsley are included. These could be omitted. Conversely, if liked, these may be used in the plum tomato version above.

Adapted from Carol Field, In Nonna’s Kitchen: Recipes and Traditions from Italy’s Grandmothers.

Serves 4 for 1 ¼ pounds spaghetti

To prepare tomatoes

Blanch the almonds.

Peel the tomatoes for more concentrated flavor. (Film the bottom of a pan with water. Cover and bring to simmer. Simmer tomatoes until skin is loosened, about 45 seconds to 2 minutes, depending on tomato.)

Cut tomatoes through the equator and remove seeds. Chop the tomatoes roughly.

To make the pesto