Harvest the tender center leaves at the heart of the plant, cut directly at the base of the leaf and collect.
Outer leaves can be used too, but can be bitter so might need to be cooked or blanched.
Endive lettuce is technically a chicory, and is believed to have originated in Egypt and Indonesia. It has been cultivated in Europe since the 16th century.
Endive lettuce is typically used as a salad green to add dimension to the mix; Leaves can be bitter, so most of the time the tender inner leaves at the heart of the plant are used, as they taste more sweet. Mature outer leaves can also be cooked and blanched to reduce bitterness.