Christmas wafer (polish: opłatek, plural opłatki; lithuanian: kalėdaitis, plural kalėdaičiai; slovak: oblátka, plural oblátky) is a catholic christmas tradition celebrated in poland, lithuania, and slovakia. the custom is traditionally observed during kūčios in lithuania and wigilia in poland on december 24. the unleavened wafers are baked from pure wheat flour and water, are usually rectangular in shape and very thin; they are identical in composition to the altar bread that becomes the eucharist at the consecration during mass in the roman catholic church. the opłatki wafers are embossed with christmas-related religious images, varying from the nativity scene, especially virgin mary wit...

Source: Wikipedia