It’s rare that a sous chef manages to one-up his former commander. But arguably, that’s what newly installed Beaker & Flask honcho Anthony Walton did when his mentor, Ben Bettinger, jumped ship in March 2012 to open Imperial with famed chef Vitaly Paley. Inspired by fresh finds and his Midwest-Southern roots, Walton collages comfort-food classics and contemporary techniques for an impressive reinterpretation of bar food. Make no mistake: Beaker & Flask remains one of the city’s craft cocktail destinations. But as word of Walton’s upscale cocktail cuisine spreads, the bartenders might need to shake even faster to keep up.