Cold weather is on its way, and it's time to harvest basil before the first fall frost decimates it. What to do with all that basil? Make pesto, of course.
Classic pesto was born near Genoa in Italy's Liguria region. Many believe that basil grown in this part of the Italian Riviera is sweeter and superior in taste to that grown in other parts of Italy. This is due both to the variety grown (basilico Genovese) and to the closeness to the sea, which creates a special microclimate. Other basil varieties are considered too sharp in flavor, so only the young, tender leaves are used. Look for shorter stalks with no sign of flower buds.
The Italian word pesto means pounded, and the main ingredient of the sauce is basil. The herb was traditionally crushed with a mortar and pestle, made to let go of its fragrance and flavor, and then blended with olive oil for the right consistency.
Early versions were made with just three ingredients: basil, olive oil and salt. Today, these are usually complemented with pine nuts, cheese and garlic. The amount of each ingredient can vary, creating subtle differences in the recipe from town to town and house to house. Each cook adds a unique touch
Good chefs use only the freshest basil, the highest quality olive oil, sea salt and mild Italian garlic. Ligurian olive oil is very light and fruity. Many chefs find table salt too harsh-tasting for this uncooked sauce, and use a good sea salt instead. And American garlic is often more strongly flavored than that grown in Italy, so add it with care; you want to taste the basil, not the garlic.
Traditional pesto calls for pine nuts, which are expensive, so creative cooks began substituting. Walnuts are common, although they have a drier consistency (so the sauce requires more oil) and somewhat harsher taste than the smooth, sweet, creamy pine nuts. Inventive cooks experimentws with other alternatives: almonds, pistachios, even pumpkin or sesame seeds. Toasting the nuts softens them, altering their texture and flavor.
Sharp cheeses come in many varieties. Classic Genovese pesto is made with creamy Parmigiano-Reggiano and sharp Pecorino-Romano. The amounts and types of nuts and cheese will vary the texture of the sauce. Some add pasta water, cream or milk to achieve the right consistency.
Just as creative cooks substituted nuts and cheeses, soon they began making pesto with other greens to create other pesto-like sauces. So today we have dandelion pesto, spinach pesto, and pesto made with kale, arugula, mint, oregano, or Italian parsley. Some make a sauce using a blend of herbs, like basil, mint and parsley together. Marcella Hazan, author of Marcella's Italian Kitchen, makes pesto with olives and capers, and John Sedlar, author of Modern Southwest Cuisine, even makes a red chili pesto.
The mortar and pestle used for pounding the basil has given way to the food processor. However, some seasoned chefs believe that the traditional pounding brings out more of the aromatic ester compounds and blends the ingredients better, resulting in a creamier, more flavorful sauce than pesto made by machine. Some also clean the leaves gently with a towel, believing that immersing them in water dilutes the fragrance and flavor.
Like most things, pesto is best made fresh and eaten right away. For pesto during our cold winter months, we freeze the basil with a little olive oil; this makes it easier to use in salad dressings and other dishes. For pesto, I combine this blend with additional olive oil, nuts, cheese and a bit of garlic when I'm ready to use it.
For a great pasta sauce, use one-third to one-half cup of pesto for a half-pound of spaghetti. To form a smooth sauce, dilute the pesto with a tablespoon or two of water the pasta cooked in.
In addition to pasta, try pesto as a spread on bruschetta, bread or bagels, or as a sauce for poultry or fish. Substituted for tomato sauce, it makes a delicious pizza topped with chicken and vegetables. It is also great on grilled or roasted vegetables, like zucchini or green beans. Or use it on tomatoes with a sprinkling of feta cheese.