In Iran, the winter solstice, which falls on December 21, is hailed with Shab-e Yalda―the birthday of the sun. It's a celebration of the triumph of light over dark, good over evil. It is thought that on the longest night with evil at its zenith, light needs help to overcome darkness. On this day, families build a bonfire outside and gather until sunrise for a night of storytelling, dancing, and food. In Iranian culture, certain nutritional properties of foods are considered hot and others are considered cold (regardless of temperature or level of spice), much like Chinese yin or yang. Balance between the two is important. Summer foods are preserved throughout the year for the Shab-e Yalda feast, where they mingle with the foods of winter to symbolize the balance of seasons. Saffron and carrots, for example, are warm foods served during Shab-e Yalda to counter the cold of winter.
Try it: Saffron and Carrot Halvah