With basil at its peak, here is my method of preserving it and enjoy it fresh throughout the winter. The best known method is freezing the leaves of the plant. Personally I find that keeping the basil in oil is the best method for maintaining the color and scent of the plant. Moreover, with this method, I also get delicious, flavored oil that can be used to flavor salads, vegetables or other dishes.
Here is the simple process.
Pick basil at its peak. Basil gets too strong and bitter if it blooms and bolts.
Wash the basil leaves in cold water. The more the water is cold, the better: in this way the leaves of the plant are not likely to lose their nice green color.
Dry the basil leaves by laying them on a towel and let them dry completely without squeezing them.
Meanwhile, sterilize the jar. When the basil leaves are dry, spread a layer of basil in the jar. Sprinkle with a little salt and add a tablespoon of oil. Continue with another layer and so on, up to end the basil. Press the leaves well between one layer and another. Finish by adding so much oil needed to cover the last layer of the basil leaves. It is important that all the leaves are covered with oil, so they can be perfectly preserved.
Seal the jar and use the leaves in the months ahead, as you prefer.
Store the jar in the refrigerator. The important thing is that the leaves are always covered by the oil (if necessary, add additional oil now and then.