The trick to cooking calçots, a special Catalan spring onion, is simple: a good charcoal grill. The heat from the glowing embers is crucial to creating the perfectly scorched exterior (the black outer skin is then peeled away, leaving the tender and juicy inner bulb). Fire and smoke – along with exceptionally fresh green onions – are really the only ingredients here. The popular ritual of the calçotada, in which families and friends gather together with the sole purpose of eating calçots, traditionally takes place between the months of November and April, the peak season of this special green onion. For particularly large celebrations, groups crowd around an open barbecue, with sarmientos, or vine shoots, creating the perfect flame to blister the onions just so.

Up in Barcelona’s hills, in the El Coll neighborhood, where the city ends and the sky is cut by the spiky shapes of the pine trees in Collserola Park, Agreste de Fabio & Roser is sprouting up. Emphasizing sustainability and healthy eating, the restaurant is creating delicious dishes that merge Catalan and Italian traditions with contemporary flourishes. Room manager Roser Asensi and her partner, chef Fabio Gambirasi, created this project (the name means “bad weed” in Spanish) less than a year ago and people are already singing their praises. On a recent visit, we could hear words of admiration from different guests flying around the room over the course of our meal.

At first glance, Restaurant Roma doesn’t appear to be anything out of the ordinary. The nondescript brown tiles covering the floors, the dark wood bar, the vaguely Mediterranean-inspired wall décor and the rectangular paper Ikea lamps are similar to those at hundreds of other midrange restaurants throughout Barcelona. Situated on a quiet street in residential Sant Gervasi, Roma isn’t somewhere you’d be likely to come across accidentally, nor is it the kind of place you’d happen to hear about, unless you (or your aunt, or coworker or a friend of a friend) lived nearby. And that would be a shame because the food at Roma is good – ridiculously delicious, in fact.

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.