To show you better what I mean, here is what not to do:
Why? Well, it's because the artichoke stalk contains tough fibres that run up into the heart. These don't cook well (if at all) and are very unpleasant to eat. Cutting the stalk off with a knife, like in the photo, leaves the fibres in the heart intact.
Here's how to do it: do not cut the stalk, but break it off, as shown here:
Hold the artichoke firmly on the edge of a table with one hand, then bend the stalk sharply with the other hand until it breaks off, bringing with it most of the fibres I mentioned earlier. It is worth noting that this is much easier to do when the artichoke is really fresh. Once the stalk starts to soften, it will bend without breaking properly.
To sum up: When preparing an artichoke for cooking, do not cut the stalk, but break it off instead.
Important: it is quite different for the
small purple artichokes, which can be eaten with their stalk (and everything else).