Summer's best herb is, arguably, basil. Gnocchi with pesto has to be one of the brightest stars in Italy’s culinary universe, or indeed among great dishes generally. Basil also figures prominently in the cooking of other Mediterranean countries, and Thailand has its own special love affair with this herb. No surprise there, as basil originated in Asia. Other countries in Asia’s warmer regions feature basil in their cooking, also.
The most common form, sweet basil, is Ocimum basilicum, a member of the mint family. This is the familiar green basil found in every garden center in spring. Several other species and varieties are cultivated, and there are some hybrids, also. Thai basil has overtones of anise or licorice, and grows larger than Italian varieties. Botanically, it is O. basilicum var. thyrsiflora. Lemon basil, another popular garden subject, is a hybrid, O. x citriodora.
We started seeds of four basil varieties this season (left to right in the image): Boxwood, Red Rubin, Siam Queen and Mammoth. Siam Queen is (not surprisingly) a Thai basil cultivar; the others are all sweet basils. Mammoth produces huge leaves that are suitable for wrapping food for steaming or for making pesto. Red Rubin has a citrusy character and deep purple foliage. It is also less inclined to revert to green than some of its red cousins. Boxwood forms a tight mound about the size of a soccer ball, thickly overgrown with petite leaves. It makes a great border plant and has plenty of basil flavor.
Although basil turns up in garden centers in April, we like to wait until after Memorial Day to plant it, when the soil has thoroughly warmed. Basil resents cold. If set out too early and they get a chill, the plants will often be stunted for the rest of the season. The plants grow so rapidly in summer heat and humidity that if planted now they will be ready in a few weeks, in time for the first tomatoes. We started our seeds April 30, and they are ready to transplant now.
Basil famously partners with tomatoes in many dishes. It also goes well with cucumbers, and in soups generally. You will nevertheless run out of things to do with fresh basil this summer, because the harvest is likely to be so abundant. Don’t bother drying the surplus; dried basil tastes like hay. Instead, preserve the flavor with fat, then freeze it. There are two ways to do this. Either combine about a tablespoon of basil with a stick of softened butter, form into a log, wrap in foil and freeze, or, make pesto, leave out the cheese, and freeze in small portions. Add cheese after thawing, and use like fresh pesto.
Another way to preserve basil flavor is to make vinegar. For this purpose, I prefer to use a red basil, because it imparts a nice color to the finished product. Any type of basil will work, however. Harvest as many basil leaves as you like and pack them tightly into a measuring cup, but not so tightly as to crush them. For each cup of leaves, measure half a cup of white wine or rice vinegar. Place the leaves in a suitable jar, cover with the vinegar, and use a wooden spoon to tamp down the leaves so they stay submerged. (You may have to do this again a time or two over the next several days.) Place the jar in the refrigerator, and note the date. After two weeks, strain off the vinegar, discard the basil, and replace it with a freshly harvested batch. Return the vinegar to the refrigerator for two weeks more. Strain off the vinegar, discard the basil, and store the vinegar in a sterilized bottle in the refrigerator for up to 6 months.
Basil-flavored olive oil is dreadfully expensive in the market, but you can make your own at home. Use about a cup of loosely packed leaves for a cup of extra-virgin olive oil. Bring a large pot of water to a boil, add the leaves, blanch for 5 seconds, drain into a colander and run cold water over the leaves to set their color. Pat dry with paper towels and place the leaves in a double boiler with the oil. Bring the water in the double boiler to a simmer, and steep the basil in the oil for 10 minutes. Transfer to a blender jar and let cool. Blend well, then place in the refrigerator overnight. The next day, bring the oil to room temperature. Strain it first through a fine sieve to remove most of the solids, then strain through a coffee filter previously moistened with a few drops of canola oil. (This prevents the filter from soaking up much of your product.) The second straining can take all afternoon, so be patient. Store the finished oil in a sterilized bottle in the refrigerator, and use within six months. Drizzle it over grilled chicken, or practically anything else!