The dried pods of the climbing orchid Vanilla planifolia were highly prized by the Aztecs in Mexico, who used them as a flavouring, above all for the popular cocoa drink xocolatl. When Spanish conquistadors under Hernando Cortez invaded Mexico in 1519, they took the cocoa bean with them back to Europe but they didn’t take the heavenly spice the Aztecs called tlilxochitl (‘black flower’). It took another 100 years or so to reach Europe, brought over by French-speaking travellers from America. Vanilla plants were exported to Europe, where they flowered and thrived in the damp climate of princely and royal hothouses. But what a disaster – the plants didn’t produce any fruit! The much sought-after, long, thin vanilla pods containing thousands of tiny black seeds remained elusive.

Why the plants were sterile in their new environment remained a mystery for a long time, until finally in 1837 the Belgian botanist Charles Morren discovered that, as a hermaphroditic plant, the vanilla orchid cannot pollinate itself. In order to reproduce, it needs particular species of bees or hummingbirds which are found only in Mexico and South America. While gathering nectar, they pierce the membrane between the male and female organs so that the pollen is transferred. For the first time, Morren managed to artificially fertilize the vanilla flower and cultivate the coveted yellowish green pods in a hothouse. To this day, every single vanilla blossom outside Mexico has to be ‘deflowered’ by hand with the aid of a splinter of cactus or bamboo. Incidentally, the plant takes its name from the Spanish word vainilla, meaning a small sheath or pod.

In the 18th century the French took the plant from Mexico to the Île Bourbon (now Réunion), an island in the Indian Ocean named after the French royal house. Today, Bourbon vanilla with its well-balanced, darkly intense aroma is also cultivated on Madagascar and Comoros. Mexico continues to produce vanilla that is slightly softer, sweeter and mellower in flavour. Vanilla pods from Tahiti (Vanilla tahitensis) taste more floral, almost musky, whereas those from Indonesia tend to be more woody and smoky in taste.

A single vanilla pod contains around 130 different aromatic components. However, the most important factor is the vanillin content of the pod, which can vary between 1.5 per cent (in Sri Lanka) and 2.75 per cent (in Indonesia). In order to release their aroma, the freshly picked pods are immersed in hot water (Bourbon vanilla) or steam (Mexican vanilla) and fermented for up to four weeks.

Vanilla goes very well with all kinds of sweet dishes, but also adds a distinctive flavour to cocoa, milk, punch and coffee. Used in tiny amounts, it will enhance fish soups, white meat, mussel dishes and cream of vegetable soups.

To finish with, here are a couple of tips: don’t throw away vanilla pods after you’ve scraped out the seeds – bury them in sugar and store in an airtight glass container. This is real vanilla sugar – it tastes much more intense than the commercially available variety, which contains artificial vanillin distilled from wood pulp. The vanilla pod itself has the most intense aroma, not the black seeds contained in the fleshy pulp, so whenever possible, add the pods to the cooking liquid and remove them before serving.