[header] How to cut iceberg lettuce [title] Remove the core. [step] Place the head of lettuce onto its side with the stalk facing your sharpened knife. Starting from the bottom of the stem, cut about 1 inch (2.5 cm) into the lettuce and discard. 
[substeps] Alternatively, you can smack the stalk against your countertop so that it breaks from the inside, making it easy to remove the core with your hand. However, this may cause bruising on the leaves.