As the legend goes, a 19th-century Catalan farmer was out experimenting in his fields when he came up with a new kind of longer, juicier green onion, the calçot. In creating the onion, the farmer produced much more than a new vegetable; he also paved the way for the rise of an idiosyncratic, and distinctly Catalan, cultural event.

Dear Culinary Backstreets, In just about every restaurant or bar I’ve been to in Barcelona, I’ve seen a dish called “tortilla.” What exactly is a tortilla and can you recommend any places where they are done especially well? Although it would seem that much of the world imagines the inhabitants of Spain subsisting largely on paella, the truth of the matter is that it is the tortilla española, also known as tortilla de patatas (truita de patata in Catalan), that  really holds the place of honor in the hearts and stomachs of Spaniards. Often translated into English on menus as “potato omelet,” this hearty round cake of potatoes, eggs, olive oil and salt has nothing to do with the traditional French omelet, nor does it have anything in common with a Mexican tortilla. At its most basic, the Spanish tortilla is made by frying up a thick mass of sliced potatoes and eggs in olive oil and then slicing it into savory wedges.

Spain has not traditionally been known as a country of great bread, although there are some exceptional old tahonas (bakeries) scattered around here and there. But after long decades of eating poor-quality breads, typically white or light bread with excessive additives, Spaniards are finally developing their taste for the staple. In fact, the culture of bread in Spain is in full fermentation right now.

Editor's Note: Sadly, this spot is now closed. Everyone knows that Germany and France can both make a mean loaf of bread. But what about Spain? When was the last time you heard someone say something like, “What this meal really needs is some delicious Spanish bread!” You’ve never heard anyone say that and the reason is that the bread in Spain is, with few exceptions, decidedly mediocre, with even the smallest bakeries producing the majority of their “fresh-baked” product using partially baked or frozen dough made in factories using industrial yeasts and preservatives.

A hidden culinary sanctuary, El Passadís del Pep may be located in one of the most visited quarters of Barcelona, but it’s out of sight of anyone who isn’t looking for it. Once you go down the long corridor that leads to the restaurant, you don’t need to do anything, and that includes choosing what to eat. From the moment you sit down, the “house” offers you your first bottle of cava, and the celebration of food and life begins. There is no menu and there are no “daily specials,” just whatever Joan Manubens and his team decide to cook that day. The restaurant, whose name means “Pep’s Corridor,” specializes in cocina de mercado, or market cuisine, prepared in a simple, traditional Mediterranean style. As if in a ballet, the show begins when the waiters start to dance around you and the food arrives at the table in a continuous flow of abundance: Iberian cured ham, anchovies, typical Catalan bread rubbed with tomato; sautéed baby squid with rice and garlic; choice shellfish such as cañaíllas (a kind of sea snail) prepared in such a delicate way that all the natural flavor is retained; velvet crabs or spider crabs cooked without any ingredient that could detract from their natural essence.

Editor’s note: This is the penultimate installment of “Best Bites of 2012,” a roundup of our top culinary experiences over the last year. Stay tuned for our final “Best Bites” dispatch, from Istanbul, tomorrow. Restaurant Roma We hadn’t planned on bringing in La Nochevieja at Restaurant Roma, but it was nearby and we didn’t feel up for public-transport adventures on New Year’s Eve. Situated on a quiet street in the upscale but untouristy Barcelona neighborhood of Sant Gervasi, Roma is thoroughly nondescript – a neighborhood joint frequented by neighborhood people of a certain age. The wood-paneled walls, racks of Maxim magazines and TV mounted in the corner kept our expectations pretty low.

Dear Culinary Backstreets, I’ll be in Spain during the December holidays and I’m wondering if Barcelonans eat any special meal on Christmas? If so, what is it and where in the city could I try it?

Mushroom hunting has an irresistible, magical pull. Composer John Cage, an avid mushroom collector, found them an integral part of his creative process, once writing: “Much can be learned about music by devoting oneself to the mushroom.” Every fall, thousands of Catalans likewise find themselves under the mushroom’s spell, following the elusive fungus’s silent melody into the woods, a rustic wicker basket in one hand and – more and more these days – a GPS-enabled smartphone in the other.

The large banner in La Nena chocolatería proclaiming “No Hay Alcohol” (strung up between a rocking horse and a wooden toy kitchen) makes it fairly clear that this is not a place for sophisticated conversation and cocktails. That doesn’t mean that La Nena (which means “The Girl” in Catalan) doesn’t cater to any other vices. Indeed, its delicious homemade cakes, pastries, hot chocolates and savory snacks tempt the residents of Barcelona’s Gràcia neighborhood on a daily basis.

Through the Daily Beast, we’ve just been introduced to the literary character Pepe Carvalho, Barcelona’s “gastronome private eye.

If La Plata is good enough for Paul Hewson, it’s good enough for everyone. More commonly known by his stage name, Bono, Mr. Hewson ate here in June 2009 a few nights before kicking off U2’s 360° world tour at Camp Nou in Barcelona.

Be it kvass in Russia or boza in Turkey, every nation seems to have one of their own, a locally loved drink that to most outsiders comes off as a particularly strange brew. In Spain, that drink is horchata, a unique and deliciously refreshing concoction made from chufas (tigernuts), water and sugar. Served chilled, horchata is beloved all over the peninsula.

Viena is the love child of an Austrian ski lodge and a McDonald’s. This Catalan fast-food joint – which has become an obligatory foodie stop thanks to New York Times food writer Mark Bittman, who famously wrote that Viena’s flauta de jamón ibérico was the best sandwich he’d ever had – dishes up fast and delicious grub with a side of kitsch.

Can Paixano, the kind of timeless dive that could soon be extinct due to the rise of Western chains, is an obligatory stop for anyone wanting to taste a slice of the real Barcelona. And the bar’s location in Barceloneta, the traditional fishermen’s quarter where the old port meets the beach, provides the perfect setting.

Catalan owners, Filipino chefs and a menu offering comfort food inspired by the cooking of Iberian sailors: La Flauta, a restaurant-cum-tapas-bar that goes long both on good taste and good value, is an excellent reminder of the benefits of Barcelona’s being a port town.