Red onion

An onion with red-purple outer layers. The colour is anthocyanin pigment. Acid turns it bright pink; alkali and long heat turn it grey-blue. It is milder and sweeter than a brown onion, so it is the usual choice to eat raw. Slice it thin and put it in acid, such as lemon juice, to soften the raw sulfur taste. Squeeze it with your hands to break the cells so the acid gets in faster.