Red butter lettuce is very similar to green butter lettuce but with reddish leaves. Butter lettuce forms cup-shaped leaves that are loose and delicate. The flavor of butter lettuce as its name suggest is buttery and slightly sweet. Butter lettuce also known as Boston and Bibb lettuce, is a leaf lettuce. Leaf varieties have loose heads and are known as the "cut and come again" lettuces as they can be harvested multiple times from a single plant.