Most of the time, Basil should be used fresh. In recipes it is generally added at the last moment. Cooking it quickly destroys the meal. The fresh herb can be kept for a short time in plastic bags in the refrigerator. Using a freezer will allow for it to be kept a longer time. In both cases, it needs being blanched quickly in boiling water. The dried herb also loses most of its flavor, and what little flavor remains tastes very different, with a weak coumarin flavor, like hay.
Mediterranean and Indochinese cuisines frequently use basil. In Mediterranean cuisines it is often combined with tomato. Basil is one of the main ingredients in pesto—a green Italian oil-and-herb sauce from the city of Genoa. The other two main ingredients of Pesto are olive oil and pine nuts. The most commonly used Mediterranean basil cultivators are "Genovese", "Purple Ruffles", "Mammoth", "Cinnamon", "Lemon", "Globe", and "African Blue". Chinese also use fresh or dried basil in soups and other foods. In Taiwan, people add fresh basil leaves into thick soups. They also eat fried chicken with deep-fried basil leaves.
Basil is sometimes used with fresh fruit and in fruit jams and sauces. Most commonly this is done with strawberries, but also raspberries or dark-colored plums. Some people say that the flat-leaf basil used in Vietnamese cooking is more suitable for use with fruit.