The baking of a key inside a bread is a non-Jewish custom which has its foundation in Christian, and possibly even earlier, pagan culture. At least one old Irish source tells how at times when a town was under attack, the men said, “let our women-folk be instructed in the art of baking cakes containing keys.”[7]
Keys were traditionally manufactured in the form of a cross, the traditional symbol of Christianity,[8] a physical item all Christian commoners would posses in their home.[9] On Easter, the Christian holiday which celebrates the idea of Jesus ‘rising’ from the dead, they would bake the symbol of Jesus—the key shaped like a cross—into or onto a rising loaf.[10] This was not only a religious gesture, but the bread was a special holiday treat. Sometimes these breads were wholly formed in the shape of a cross; other times the shape of a cross was made out of dough and applied on top. In the context of historically baking a key into bread—the key itself, intrinsically, was a symbol of Christianity and by extension symbolized Jesus ‘rising’ in the dough.[11]
Connection to Passover
The modern Jewish custom of baking the symbolic shlissel challah, annually takes place on the shabbat immediately following the holiday of Pessah, when tens (if not hundreds) of thousands of religiously observant Jewish women[12] practice this observance.
In Christianity, baked goods associated with keys are commonly called ‘Easter breads,’[13] and in Europe they are also known as ‘Paschals,’[14] as the holiday of Easter in the East is known as ‘Pascha’ or ‘Pascua.’ This is most likely the reason Christians often call Easter breads baked with keys Paschals.[15] Before the Romans destroyed the Beit HaMikdash (the holy Temple) in Jerusalem, the focus of the Passover holiday for the Jewish people was the Korban Pessah (lit. Pessah sacrifice, also known as the Paschal Lamb[16]). Within Christianity, Jesus is known as the ‘Paschal Lamb.’
Geographic Origins
Professor Marvin Herzog, a world renowned Yiddish linguist at Columbia University tells that dough twisted in the form of a key (among other shapes such as a ladder) were found to top challah loafs in Poland, “…the distribution of some of these things was a regional matter.”[17] As an example of the regionality, Prof. Herzog created a map demonstrating where dough was shaped as a ladder and placed on challah, and how it was specific only to certain communities and was not universal. Insomuch as a ladder motif was regional, it can be conjectured that the use of a key or key motif could have evolved the same way. Both a ladder and a key are symbolic as tools that could metaphysically help one attain heaven, as they both help ‘gain access.’