A twelve-dish Christmas Eve supper is traditionally prepared in many Central European and Northern European cultures, especially those that were formerly part of the Polish-Lithuanian Commonwealth, including Polish, Lithuanian, Ukrainian and Belarusian. The meal (Belarusian: куцьця, Lithuanian: kūčios, Polish: wigilia, or wieczerza wigilijna, Ukrainian: Свята вечеря, Sviata vecheria) consists of twelve meatless dishes representing the twelve months of the year. The tradition of the supper can be traced back to pre-Christian times and connected with remembrance of the souls of deceased ancestors.
In some parts of Poland a similar tradition of thirteen meatless dishes on Christmas Eve is practiced.
The specific dishes may differ from country to country, but many of them are universal. Due to the Nativity Fast, no meat, eggs or milk (including cheese) are allowed during the supper. Thus fish, mushrooms and various types of grain are the main offerings.
In Poland the supper begins with eating soup. The ritual in Ukraine is to start Sviata Vecheria with Kutia. 'Kutia', poppy milk (aguonų pienas) together with kūčiukai are served as a dessert and forms a significant part of the Lithuanian Christmas Eve menu. Poppy seeds are widely used for Christmas Eve dishes, because they symbolise abundance and prosperity. In this respect, it was believed that varenyky, which are also a symbol of prosperity, with poppy-seed filling when served at Ukrainian Sviata Vecheria have the most magical potential for bringing prosperity and fecundity to the villager.