...............except when it was a day old.
Happened into a site this am - can't find it again - with great photos of how he did it. May be old hat to some, but not to me.
Hold the leaf head down & slash down each side with a goodly sized (sharp, of course!) knife. SO quick.
I know the method you mean Tim. It works especially well on curly kale. The secret is the angle at which you hold the knife: 45º or more from the horizontal with the handle lowest, to give a scything action rather than a chopping one. Looks easy when you've spent a day practising for a demo, but when you have just a few leaves to do, a few times a year, you kind of lose the knack again.
Geoff.