After several months of braising greens, earthy roots, and winter squash, March is finally here, bringing with it the promise of new seasonal treats around every corner of the Ferry Plaza Farmers Market. It’s my favorite month to explore the bright flavors of spring and challenge myself to find a new ingredient to add to my seasonal favorites. My pick for this week — Calçot onions (pronounced “kal-sot”) — comes from farmers Marty Jacobsen and Janet Brown at Allstar Organics.

“It’s a style of growing as well as a stage of growing that produces a true Calçot,” Janet told me. “They are cultivated when they produce seed rather than the bulb, which is what most other varieties are grown for.” To achieve a Calçot-style onion, whole onions are planted in the fall and when the shoots appear, the soil is hilled up around the base of the stalk so the bottom remains white and the stalk grows tall. Janet says any variety of onion can be used to grow Calçots as long as you use this method.

In Spain Calçots are celebrated in the Catalonia region with festivals called Calçotadas, which take place in late winter around February and March. Traditionally, the onions are charred over large open-fire pits and eaten with a romesco-style sauce and accompanied with red wine or cava.

This is the first year that Allstar Organics has attempted this method of cultivation, and so far they are quite pleased with the results. “Calçots have a great true onion flavor, and the high sugar content really helps them caramelize beautifully, but they are also pretty fantastic raw,” Janet told me. Even though they are just making their seasonal debut, they have already caught the eye of several chefs. Look for Calçots this month on the menus at Boulettes Larder and Bouli Bar,Prospect, Bocanova, Buckeye Roadhouse and Madera, and to try them for yourself, stop by the Allstar Organics stand on Saturdays at the Ferry Plaza Farmers Market through the month of March.

For more market updates and seasonal tips, follow Lulu Meyer @farmersmarketlu or check out @CUESA on Twitter.