Yellow Frisee Lettuce

Frisee often appears in mesclun and other salad mixes, because the green is extremely laborious and therefore expensive to produce as a sole salad ingredient. In addition, its distinctive flavor can be overwhelming, and a small amount can go a long way. It is generally served in loose chunks in salad to highlight its exotic feathered appearance.
When growing, frisee resembles lettuce, with a loosely arranged head of curled leaves around a central stalk that is harvested once.