Roncero trained to be a chef at the Escuela Superior de Hostelería y Turismo de Madrid. When he finished his studies in the 90s, he had his first contact with the world of work staging at the restaurant Zalacaín (3 Michelin stars), and later in Madrid's Ritz hotels. In 1998 he joined Ferran Adriá's team, and in 2000 he was named Head Chef at the Casino de Madrid. After taking over at Casino he received a Michelin star in January 2002. In 2004 he was responsible for organizing and preparing the gala dinner for the royal wedding, together with Adriá and Juan Mari Arzak. He also began writing for El País. He currently writes for vaious national and international publications, and has travelled all over the world giving lectures. Premio Nacional de Gastronomía, 2006.