Popularized by Paul Prudhomme, the term “Holy Trinity” has entered the culinary lexicon to designate the three ingredients that form the base of Cajun and Creole cuisine. Onions, bell peppers (or sweet peppers as we say in Louisiana French), and celery are mandatory in our south Louisiana homes. Most of the dishes in our cookbooks urge apprentice cooks to start by cutting out these three ingredients and simmering them before adding meat or seafood depending on the recipe. Despite our familiarity with them, people do not usually question the origins of these essential components. Their combination is perhaps a variation of mirepoix, a similar mixture in classic French cuisine, with carrots instead of bell peppers. If they seem to have always been on our plates, it is because they have been in our gardens and at the bottom of a pot for thousands of years.
The onion is so ancient and widespread that we do not know exactly where it came from. Since we find it in the East as in the West, we suppose that the wild onion, from which we cultivated the species we have today, came from somewhere in Central Asia. Under the ashes of Mount Vesuvius in Pompeii, there are traces of gardens where it grew. Charlemagne advised his cultivation. It was such a necessary food that the first European settlers brought it with them to the Americas. They were however surprised to see that the onion was not unknown to the First Nations. It is claimed to have several qualities, ranging from an aphrodisiac to the relief of insect bites. Despite its low nutritional value, its greatest contribution is taste.
If the Europeans did not introduce the onion to the New World, they brought the pepper back with them. Upon his return from his first transatlantic trip, Christopher Columbus introduced this spicy fruit to Europe. Like the tomato, it is botanically a fruit and not a vegetable. However, it was not until the 1920s that we discovered how to remove the capsaicin, which gives it its hot taste, to develop the sweet pepper. On the Scoville scale, it is the weakest, at the other end of its cousins, cayenne and habanero. Its bell shape gives it its English name and its sweetness its French appellation.
Celery is perhaps the least appreciated with its weedy aspect, perhaps because of its bitter taste, its habit of growing wild in swampy areas and its false reputation for being so weak in calories that chewing it burns more than it provides. It is rich in nitrate, which facilitates digestion and blood circulation. It was used as a medicinal herb for pain relief. It, too, has been cultivated and consumed for millennia, recommended by Charlemagne as well.
Before learning how to make a roux, we begin the real learning of our cuisine by chopping the “Holy Trinity”. Its aroma as it cooks is divine.