Back in 2017 Mariela Camacho, the eldest daughter of Mexican immigrant parents, was baking sourdough loaves for coffee shops in Seattle when she decided to lean into her heritage and learn to bake conchas, the catcher’s-mitt-size sweet buns commonly found in Mexican panaderias. The problem: She had no idea how to make them. “My family cooks, but they don't bake, so I had to figure it out myself,” she said. “Nine years ago conchas were not cool, so I had to basically teach myself.” Today Camacho bakes colorful conchas in modern flavors like Earl Grey and vanilla, hot chocolate with saffron and guajillo, and brown butter lavender at Comadre Panadería , her bright pink shop in Austin, Texas. A concha from Vato in Brooklyn with yuzu curd, totomoxtle, and craquelin. Photo by Paco Alonso She’s far from alone. Contemporary conchas are popping up across the country: in New York at Vato and Cosme; in Los Angeles at Santa Canela and My Panecito; in Vermont at Atla’s Conchas.…