Fill a saucepan with 500 ml of water and bring to the boil. One can decide whether to add salt immediately (about 10g of rough salt) or at the end of the cooking process.
Prepare the artichokes, discarding the tougher outer leaves so as to use only the heart of the vegetable, chopping them finely and excluding the tip. To avoid oxidation and discolouring sprinkle the artichoke with the juice of half a lemon as soon as they are cut. Mix them also with the fresh, finely-chopped rosemary.