A 100g portion of pesto contains 534 calories as well as 50g of fat, 12% of which is saturated and 30% is monounsaturated. Although high in both calories and fat, this sauce also contains many beneficial nutrients, and a little goes a long way. Consuming it in moderation can make it a healthy addition to your diet, and since the fat content in the sauce is mostly unsaturated, this promotes a healthy heart.

In the same portion, this sauce contains 56 IU of vitamin A, which supports healthy vision and 6mg of vitamin C, which acts as an antioxidant and tissue-builder. In addition, there is 2.2mg of iron and 588mg of calcium. Iron supports our red blood cell count and calcium builds strong bones. That's not all, because pesto also contains a lot of protein, with 18g per 100g. The fresh basil in the sauce boosts the number of flavonoids, which help to maintain a healthy cell structure and combat free radicals.

When freshly made with no preservatives, the sauce should be kept in a sealed, airtight container such as a jar. It can then be stored in the refrigerator for about a week. The sauce also lends itself well to freezing. To do so, the ideal method is to scoop servings into an ice cube tray – this makes smaller portions to handle when defrosting. As an alternative, use plastic freezer bags to store manageable quantities of sauce in the freezer. When frozen, it will keep for around 6 months. To freeze it for longer, use a small jar or plastic container – this will keep for up to 12 months.

The best advice for how to prepare pesto is to use a blender or food processor when making it fresh as opposed to a pestle and mortar, which is much harder work. Blend together fresh basil leaves, pine nuts and peeled garlic cloves together with Parmesan cheese shavings and olive oil.

A handy tip is that you don't have to stick to these ingredients – experiment with walnuts and cilantro or mint along with Romano cheese as substitutes for the standard ingredients. Anyone with a dairy intolerance can leave out the cheese completely.

The name 'pesto' is the past participle of the Italian verb 'pestare'. This means 'to crush' or 'to pound', which refers to the preparation method for the sauce. Officially, the word is generic for anything that's produced by pounding. In Italy, it relates to several types of pesto, but the Genovese version is the most popular, which is the traditional green paste commonly used in cooking.

Including basil as the main ingredient in the sauce is only a fairly recent occurrence. Although the sauce is thought to date back to Roman times, the inclusion of basil was first documented during the middle of the 19th century when Giovanni Battista Ratto, a gastronomist, published "La Cuciniera Genovese", a book about Italian cooking.

https://en.wikipedia.org/wiki/Pesto