Perhaps due to it being such a simple dish similar to many other egg-based omelets, little is known of the exact origins of the Spanish omelet. The first reference to the dish is believed to have been found in an anonymous letter addressed to the court of Navarre dating from 1817. The letter details the poor conditions of the populations around Pamplona and the Ribeira, stating that many make do with only a few eggs cooked as a tortilla with potato, breadcrumbs and other simple ingredients to feed five or six people. One popular tale states that it was an army general called Tomás de Zumalacárregui who first invented the dish as a cheap and easy way to feed his troupes during the siege of Bilbao, and yet another version of the story states that it was in fact a poor farmwife who invented the dish, one day when the general visited their farm and requested to be fed.
For something so simple, there is considerable room for debate when it comes to what the authentic recipe for a Spanish omelet actually is. In fact, the controversy surrounding the inclusion or not of the humble onion in tortilla is one that could could keep some Spaniards talking for hours. Purists would have it that a true tortilla de patatas would only contain potato, eggs and olive oil, leaving the subtle flavours of the oil and egg to give the dish its distinctive taste, but onion advocates claim that the sweetness it brings when slowly cooked down in olive oil is an essential component of what makes the dish so delicious. It is fair to say that both versions are probably equally as popular and equally considered ‘traditional.’
The moment things start to get a little more complicated is when it comes to what some might consider ever so slightly more fanciful additions, which range from chorizo to green pepper, cheese or even tuna. In more upmarket restaurants, chefs have featured versions including luxury ingredients, such as truffle and foie gras. As popular or as flavorsome as these variations may be, they cannot really be considered classic ‘tortilla de patatas,‘ as the inclusion of onion is as about as far as the traditional recipe is willing to stretch.
The quality and even nature of the oil is also something worth considering given the sheer volume of the liquid included in the dish’s preparation. Extra virgin olive oil is an obvious first choice, but some households may defer to a lesser-quality olive oil or even stray to another type of oil (such as sunflower), which inevitably leads to the distinctive fruity flavor of the olive being lost.
A modern variation on the use of fresh potatoes has grown in popularity in recent years, which was no doubt fostered by the great Catalan chef Ferran Adrià and calls for using potato crisps instead. Since the traditional recipe requires finely sliced potato bathed and cooked in olive oil, the use of crisps may well be a clever shortcut and an interesting twist on the traditional recipe — but because the humble potato hardly ever takes center stage in many recipes, perhaps it is best left to its leading role in the tortilla.
One notable quality of the Spanish omelet is its widespread popularity throughout Spain, something which is not very typical in a country where regional differences (both culinary and otherwise) are so strongly pronounced and so proudly defended. A relatively simple dish to prepare, it features heavily on the glass top counters of restaurants across the country and is a popular option for a tapa, the small dishes that make up Spain’s signature serving style. When served as a tapa, the tortilla is usually cut into a small squares, each of which is served with a cocktail stick.
If it is being eaten as part of a meal, the tortilla is usually served in a large triangular slice and may come accompanied by some salad or tomato. It’s a popular dinner time meal for those looking for a light dish before bedtime, and many households keep a tortilla around the kitchen for an easy snack or meal. The dish can be served (and enjoyed) either warm or at room temperature, with the latter being more frequent if the dish is being eaten as a tapa. A homemade tortilla served as a meal may sometimes still be a little soft inside if the egg has not been left to cook through — although this may not be to everyone’s liking, it’s a rare pleasure for those who do enjoy it.