Complex sentence: Although called "salsa" in Spanish, it is, rather, a thin, smooth sauce (akin to worchestershire) meant to be used while cooking or, popularly, tableside to flavor one's food when cooking.
Split into simpler sentences: Although called "salsa" in Spanish, it is, rather, a thin, smooth sauce (akin to worchestershire). It is meant to be used while cooking or--popularly--at tableside to flavor one's food when cooking.