In preparing food to eat on Yom Tov, we must be sensitive to the fact that some foods involve so much hard work which can be done prior to the holiday that it is recommended they not be bothered with on Yom Tov or done only in an unusual manner. An example of this is cutting off excess leaves from vegetables, which cannot be done with the scissors that are normally used for this purpose. Even so, foods whose preparation is complicated can be cooked and eaten on Yom Tov. Kundas (artichokes) and akaviyot (cardoon) are examples of such foods. The kundas is identified as Cynara scolymus – the Globe artichoke – a perennial, thistle-like plant that grows to a height of one meter. Akaviyot are identified as Cynara cardunculus – cardoon – which is a member of the thistle family and related to the Globe artichoke.
Whole Globe artichokes are prepared for cooking by removing all but approximately 5-10 mm of the stem and (optionally) cutting away about a quarter of each scale with scissors, which removes the thorns that can interfere with the handling of the leaves while eating. And while the flower buds of the cardoon can be eaten much like the artichoke, the stems are generally made edible by blanching, when they are tied together and stored for some time.
Another type of food that cannot be eaten without effort is nuts. The Gemara quotes a baraita which permits wrapping nuts in cloth and cracking them, even if the cloth will tear. The Ran presents this as a case where several nuts are placed in a covering and broken all at once with a hammer. There is no concern that the cloth will tear, either because there is no intention to tear the cloth, or, as Rashi suggests, this is at worst a case of mekalkel – a destructive activity – which is not forbidden on Shabbat and Yom Tov.