Want to start an argument? Ask a couple cooks how to make pesto.

No two use the same recipe, and they don't even have to be Italian to be certain theirs is the most authentic way to get the most out of two handfuls of basil, garlic, some olive oil and pine nuts.

Whoa, wait a second. Some argue that walnuts, not pricey pignolias (pine nuts) are better.

Yeah, but plenty of experts will tell you nuts are unnecessary altogether because they dilute the taste of the basil.

But it doesn't have to be basil. Arugula or sun-dried tomatoes make a good pesto, too.

Then there's the discussion of cheese. Better to add the Parmesan after the spaghetti has been sauced or while the sauce is being pulsed to a paste in the food processor?

Food processor! Diehards will argue to the grave that pesto isn't pesto unless it's been ground by a pestle in a mortar like it was done back in Liguria, Italy.

Liguria? Pesto originated in Genoa!

No way. Pesto came from Provence in the South of France where they call it pistou.

There is no end to the debate about the origins of this delicious sauce, which has become the favored alternative to tomato sauce for a nation of pasta eaters -- that's right, Americans no longer consider pasta a "foreign food," according to a recent survey.

Since there can never be any resolution to this delicious dispute, the next best thing is to provide a wide range of opposing views. You decide which approach you prefer.

Tools

"Pesto" stems from the Italian verb pestare, which means "to pound." That's how pesto traditionally has been made, pounding ingredients by hand in a mortar, with a pestle. Nowadays, however, pesto ingredients customarily are whirred quickly into a puree with a blender or food processor.

Does it make a difference?

Yes, says Paul Bertolli, who in a cookbook he wrote with Alice Waters ("Chez Panisse Cooking") argues that pesto made by machine simply is never as good as pesto made by hand.

"Handmade pesto has a pleasing coarseness and lack of uniformity; the blender makes a slick imitation of the original," writes Bertolli.

What's more, say some, basil chopped in a blender or food processor tends to taste bitter. Matt Kramer, author of the cookbook, "A Passion for Piedmont," isn't one of them, however. "In my blind taste tests, I confess to not being able to tell the difference between the pounded and the blended," he writes.

Even among cooking enthusiasts who concur that the mortar-and-pestle is the only way to make pesto, opinions vary over which type to use. Bertolli advocates a fairly large Japanese ceramic mortar with a grooved inner surface whose grittiness simplifies the task of reducing basil leaves to paste.

Never, however, use the kind of stone molcajete for grinding spices in Mexican cooking; it yields a bit too much gritty texture for pesto.

Basil

Unless you grow your own basil, or are the lucky recipient of the bounty from a neighbor, you're subject to whatever strain the supermarket stocks. Most carry just one, and it likely is the standard sweet lettuce-leaf basil.

Regardless of variety, incidentally, pesto enthusiasts recommend that stems be trimmed from the basil before it is processed, eliminating the potential for bitterness.

Given a choice, pesto connoisseurs frequently prefer one variety of basil or another. Several favor a small-leafed basil generally called piccolo, known more formally as "basilico fino verde compatto," cultivated extensively in the Italian region of Liguria, where pesto originated.

"People say you can't make a good pesto without Ligurian basil, but that's hogwash," says TV chef Biba Caggiano, who in her back yard cultivates the standard sweet broad-leafed basil for her restuarant.

Opinions vary on how basil should be cleaned. Some prefer simply to brush or rub the leaves gently with a towel to rid them of dirt. For people who'd rather thoroughly wash the leaves, Carlo Middione, chef/owner of the Vivande restaurants in San Francisco, advocates sloshing the bunches in cold water, then putting them on thick cotton towels to drain and air-dry. Any residual water on basil adversely affects pesto's flavor, he has found.

Garlic

Though garlic is an essential ingredient of pesto, be careful not to use it too liberally, less its heat and pungency overwhelm the cool freshness of the basil.

"People here use too much garlic," says Caggiano. "It has to be kept under control."

For a standard batch of pesto -- enough to serve four, made with about two tightly packed cups of basil leaves -- one clove of garlic should be sufficient, though two or three will be preferred by most people who look for its bite.

Pine nuts

Though little and cute, pine nuts pack more potential for pesto debate than any other ingredient.

Some professional cooks refuse to use them at all, though most now concede they are as essential to pesto as olive oil and garlic.

Once the decision has been made to use pine nuts, the next question is what kind -- the familiar teardrop-shaped Chinese variety or the long, thin, light Mediterranean? The Mediterranean is preferred by connoisseurs, but they are considerably more expensive and more difficult to find than the egg-shaped Chinese.

Also at issue is whether the pine nuts should be toasted. Some cooks prefer the smoky sweetness provided by lightly toasted pine nuts, while others disregard the step as unnecessary.

"In Italy, the pine nuts are not toasted, but I do it a little bit to bring out the flavors," says Caggiano.

Regardless of which common method is used to toast pine nuts -- on a cookie sheet in a 350-degree oven or on the stove in a medium-warm skillet -- be sure to do it just briefly, lest they get scorched and spoil the fresh flavor of the pesto.

Another popular and less costly way to add nuttiness and body to pesto is to substitute walnuts for pine nuts, or to use a combination of the two. Hazelnuts also can be used.

Olive oil

Because pesto is uncooked and highly dependent on the quality of its ingredients, only a superb extra-virgin olive oil will do. With so many olive oils now available, where's a person to start? Kramer suggests looking to Liguria.

"Ligurian olive oil is Italy's most delicate," writes Kramer. "It's extraordinary olive oil, rivaled only by that produced farther south in Tuscany's Chianti Classico zone, which is more peppery. Ligurian olive oil is `sweeter,' with a lighter texture."

Cheese

While most pesto recipes call for Parmigiano-Reggiano, a hard and grainy cheese of cow's milk, Ligurian culinary historians, note Andrews, claim the first pestos actually were made with a sheep's-milk cheese.

Thus, several pesto recipes call for pecorino, a sheep's-milk cheese originally associated with Sardinia (pecorino Sardo) but now also made elsewhere in Italy, and often labeled pecorino Romano. What's more, some pesto recipes specify both Parmigiano and pecorino, with about equal measures of each.

Almost without exception, professional cooks advocate that the grated cheese be stirred gently into the pesto as the last step, thereby retaining the slight graininess of the cheese.

PESTO SAUCE

2 cups packed fresh basil leaves

6 garlic cloves, peeled

½ teaspoon salt

¼ cup pine nuts

½ cup extra-virgin olive oil

3 tablespoons unsalted butter, softened

1/3 cup freshly grated Parmesan cheese

In the work bowl of a food processor with the metal blade or a blender, combine the basil and garlic. Pulse until the basil and garlic are very finely chopped. Add the salt and pine nuts and pulse several times. With the motor running, slowly pour in the olive oil in a steady stream.

Transfer the mixture to a small bowl. Using a spatula, fold in the butter and, when it has been incorporated smoothly, fold in the Parmesan cheese. Set aside until ready to use. 8 servings.

Recipe from "Pasta with Sauces: The Williams-Sonoma Collection" (Time-Life Books).

UNPLUGGED PESTO

2 cups loosely packed small basil leaves

1 small tender spinach leaf, 4 leaves flat-leaf parsley and leaves from 1 small sprig of marjoram (if you don't have all three, include at least one and increase the amount)

Small pinch (about ½ teaspoon) coarse sea salt

2 medium garlic cloves, peeled and lightly crushed

1/3 cup grated Parmesan cheese

3 tablespoons grated Pecorino Romano cheese

About ½ cup extra virgin olive oil

1 pound spaghetti or spaghettini

Extra grated cheese for the table

Remove any fibrous ribs from basil leaves. Remove spinach rib. Wipe herbs clean with a dry tea towel. If herbs and spinach are not organic, wipe them with a barely dampened towel. Place sea salt in a large mortar. Add a few leaves, torn into fragments, and 1 clove of the garlic. Start grinding with the pestle, using a circular motion, until everything is reduced to a fine texture. Add a few leaves, and grind and gently pound until leaves and garlic are reduced. Continue in this way, adding the remaining garlic clove at roughly the midpoint, until all leaves are ground to a fine textured pesto.

As you work, keep scraping the pesto down into the bottom of the bowl to form a mound. With the pestle, gradually stir in the cheeses.

You will have a very dense mixture. Scrape pesto off the pestle and down from the sides of the bowl into the bottom of the mortar. Pour olive oil into a small pitcher or measuring cup. Add olive oil in a fine stream, stirring it in with the pestle in a circular motion. Add more oil only as the stream of oil becomes fully incorporated into the pesto. One-half cup oil makes a very "loose" pesto. You may want to use less oil for a thicker pesto. Taste and add salt as needed. Put a plate over the mortar to seal off air. Place mortar in the center of the dining table. Meanwhile, cook spaghetti in abundant salted boiling water until al dente. Add 1 or 2 tablespoons pasta water to the pesto, whisking it in with a fork. Use tongs to lift pasta, dripping wet, into individual pasta bowls. Quickly spoon a little pesto over each bowl and let each person immediately mix it into their pasta (if any time elapses the pasta will start to stick together). Place a spoon in the mortar so diners can help themselves to more pesto according to taste. Serve with grated cheese at the table. Serves 4 to 6.

Recipe from "Unplugged Kitchen" by Viana La Place (Morrow).

PESTO PIZZA

PESTO:

2 cups lightly packed fresh basil leaves, washed and patted dry

¼ cup olive oil

1 teaspoon lemon juice, optional

2 cloves garlic, minced or pressed

½ teaspoon salt

2 tablespoons pine nuts

½ cup grated Gruyere, Parmesan or Romano cheese

PIZZA:

2 tablespoons olive oil

½ pound button mushrooms, thinly sliced

2 to 3 cups ( ½ to ¾ pound) shredded Fontina cheese

2 12-inch or one 18-inch unbaked pizza crust

For the pesto: Rinse basil leaves well and pat dry before measuring. In blender or food processor combine oil, lemon juice (if used) and garlic; add basil, salt, pine nuts and cheese. Blend or process until pureed. Set aside, covered, to meld flavors.

For the pizza: Preheat oven to 450 degrees. Heat olive oil in a large frying pan over medium-high heat. Add mushrooms and cook, stirring often, until they are lightly browned and their liquid has cooked away. Remove from heat.

Sprinkle cheese over pizza crust(s). Arrange mushrooms over cheese.

Bake on lowest rack of oven until crust is browned (15 to 20 minutes for 12-inch pizzas; about 25 minutes for 18-inch). Spoon pesto evenly over pizza; return to oven long enough to heat through (1 to 2 minutes). Serve at once. Makes 2 12-inch or one 18-inch unbaked pizza.

SUN-DRIED TOMATO PESTO

¼ cup almonds, chopped

4 to 6 ounces sun-dried tomatoes, with oil

½ cup olive oil

¼ cup grated Parmesan cheese

1 tablespoon garlic, minced

1 tablespoon onion, minced

½ teaspoon oregano

½ teaspoon basil

¼ teaspoon thyme

Dash of red pepper flakes

2 tablespoons lemon juice

Everything goes into blender or food processor -- whirl till you have a thick, grainy sauce. Cover and refrigerate, or serve immediately: ¼ cup on each serving of pasta. Pass some additional Parmesan and enjoy. Serving 4.

From Susan Branch's "Vineyard Seasons."

Spaghetti Con Il Nuovo Pesto Di Rucola Di Paolo

4 cups loosely packed fresh arugula, washed and dried and coarsely chopped

2 garlic cloves, chopped

½ cup chopped walnuts

½ cup olive oil

4 medium-sized firm, fresh ripe tomatoes

Salt and freshly ground pepper

1 pound spaghetti

1 tablespoon sweet butter

Freshly grated pecorino or Parmesan cheese

Put the arugula, garlic, walnuts and olive oil into the container of a food processor or blender and puree until smooth and creamy. Add 1 of the tomatoes, peeled, seeded and chopped and puree.

Turn the mixture into a bowl, season to taste with salt and pepper, and set aside. (The sauce can be made up to 1 hour in advance.)

Bring 4 quarts of water to a rolling boil in a large pot.

Meanwhile, cut each of the remaining 3 peeled and seeded tomatoes into small cubes and drain well.

When the water comes to the boil, stir in 1 ½ tablespoons of salt and add the spaghetti. Stir it again and cook the spaghetti until al dente, or just tender, stirring frequently.

Put the butter in the bottom of a large bowl with 1 tablespoon of the sauce.

When the pasta is done, reserve 1 cup of the hot cooking water. Drain the spaghetti lightly and turn it into the bowl. Add half the sauce and the tomatoes and toss. Add the remaining sauce and tomatoes and gently toss. If necessary, add a little of the hot water and toss again if the sauce is not blended thoroughly or the pasta has dried out. Serve immediately and pass the pecorino or Parmesan cheese. Serves 6 as a first course, 4 as a main course.

Recipe from "La Cucina Siciliana di Gangivecchio."

Scripps-McClatchy Western Service contributed to this story.

Published 9/23/1998