When a recipe calls for shredding lettuce, usually crisp iceberg lettuce is the ingredient of choice. To core the iceberg, lightly tap the stem end of the head on a counter. Then twist the core off. Rinse the whole head under cool running water, including the spot where the core was. Place inverted into a colander and let dry. Cut into eight wedges and cut each wedge into thin slices for shredded lettuce.