In the previous Halachot we have explained that although Shabbat and Yom Tov are equal in their prohibition to perform work on them and it is therefore a Torah prohibition to drive a car on Yom Tov, nevertheless, certain works associated with food preparation, such as cooking and frying, are permitted.
Let us now discuss an important detail regarding the laws of cooking on Yom Tov: There are certain foods which “lose their taste,” meaning that they are as not as tasty as time goes by from the time they were cooked. On the other hand, there are other foods which do not taste any different a day or two after they were cooked.
For instance, meat cooked on the grill will begin to lose its flavor as time passes since it has been cooked and it is preferable to eat it immediately after it has been cooked. Similarly, fried vegetable, such as French fries, are tastier when eaten immediately after they are prepared and the more time goes by, they begin to lose their taste. Such foods may be cooked on Yom Tov according to all opinions since if they are prepared before Yom Tov, they would not be as flavorful.
On the other hand, regarding foods which do not lose their flavor, such as jams, fruit compotes, and the like which do not taste any different several days after they have been cooked, there is a dispute among the Rishonim if they may be prepared on Yom Tov. Some say that since these foods may be prepared before Yom Tov, our Sages forbade preparing them on Yom Tov so that one does not stand in the kitchen and cook all Yom Tov long and abstain from enjoying Yom Tov. Others rule that our Sages never forbade this. The reasons behind this matter are quoted by Maran Ha’Bet Yosef and the other Poskim in the laws of Yom Tov (Chapter 495).
Halachically speaking, Maran Rabbeinu Ovadia Yosef zt”l rules (in his Chazon Ovadia-Yom Tov, page 8) that even a food which would not taste any different had it been prepared before Yom Tov, such as jams and compotes, may be prepared on Yom Tov,, it is nevertheless preferable, wherever possible, to prepare such foods before Yom Tov. One should prepare only foods that taste better fresh, such as fried vegetables, on Yom Tov itself.
Ashkenazim rule stringently on this matter as the Rama forbids preparing “foods which do not lose their taste” on Yom Tov. Nevertheless, the Mishnah Berura writes that if one did not have a chance to prepare such foods before Yom Tov due to a lack of time and the like, one may prepare them on Yom Tov. It is likewise permissible to prepare such foods on Yom Tov while cooking them in a somewhat different manner (such as by placing the pot on the flame in a different manner than usual).
Summary: Any food which tastes better when eaten immediately after its preparation, such as fried vegetables and grilled meat, may be prepared on Yom Tov. A food which does not taste any different if it is prepared before the holiday should preferably not be prepared on Yom Tov and should be prepared before Yom Tov, as we have written.