Chiffonade is a chopping technique in which herbs or leafy green vegetables (such as spinach and basil) are cut into long, thin strips. This is accomplished by stacking leaves, rolling them tightly, then slicing the leaves perpendicular to the roll. The technique can also be applied to crepes or thin omelettes to produce strips.
This technique is unsuited to small, narrow, or irregularly-shaped herb leaves such as coriander, parsley, thyme, or rosemary due to there being less surface area for the knife to do a practical job.
“Chiffonade” means little ribbons in French, referring to the little ribbons you create while cutting.