In Slovakia, the traditional Christmas Eve sauerkraut soup is called Kapustnica.
Kapustnica is a sour, hearty Slovak soup whose defining ingredient is fermented cabbage, or sauerkraut. Christmas versions often include dried mushrooms and prunes, while regional recipes may add smoked meat, sausage, potatoes, cream or paprika. The exact ingredients vary considerably across Slovakia.
The soup is especially associated with Štedrý večer, Slovak Christmas Eve, when it is commonly served as part of the evening meal. In households observing a meatless fast, the Christmas version may omit sausage and meat, even though everyday or regional versions frequently include them.
Kapustnica is not the same as goulash, borscht or Polish mushroom soup. Its identity comes from the fermented cabbage’s sharp flavor. The name itself is related to kapusta, the Slovak word for cabbage. It is also served outside Christmas, including at New Year and in restaurants throughout the year, so “Christmas Eve soup” describes its festive role rather than an exclusive serving date.