'It runs in my blood': East Bay pop-up celebrates Mexico's most iconic baked good FacebookTwitterEmail Douglas Zimmerman/SFGATE Just as everyone was getting into sourdough kit starters and baking fresh bread loaves last year, Agueda Ulloa was longing to create something that hit closer to home. As the granddaughter of a former Mexican bakery owner, Ulloa gravitated towards Mexican pan dulce (sweet pastry bread) and realized that what she wanted to bake most was one of Mexico’s most quintessential baked goods — the iconic concha. Of all the Mexican sweet bread varieties, conchas are among the most popular. The pastry itself is best described as a rounded bread with a thick powdery sugar dome that’s etched with a sundry of linear designs. Its shape and appearance help give the traditional pastry its name, meaning seashell.