Around Christmas in Italy, you can find many delectable and decadent dolci, but the most wholesome of these holiday treats might be roasted chestnuts. Whether part of La Vigilia in Italy or the Feast of the Seven Fishes in the United States, the aromatic nuts are as important to the celebration as the much-lauded panettone. In spite of their apparent simplicity, however, making well-roasted chestnuts for the Christmas Eve meal is neither quick nor easy.

Many Italians attribute the creation of the famed chestnuts known as castagne del prete (“priest’s chestnuts”) to monks from the Campania region. Local lore holds that the monks’ process was actually a way to revive smaller, harder chestnuts that would otherwise be inedible. Over time, however, the nuts became a sought-after commodity. The time-intensive drying, roasting, and soaking process can take more than two weeks. First the nuts are spread on boards or straw mats in drying rooms called gratali. The rooms, which are often heated by wood from old chestnut trees, dry-smoke the nuts for anywhere from 10 to 14 days.

Once dried, the chestnuts will have loosened shells and skins, and be ready for toasting. In the oven, some of the chestnut’s starches convert into sugar, lending to their sweet yet nutty taste, but the process doesn’t end there. Older nuts, or those with low moisture content, can lead to tooth-cracking misery if not for the final “bath” they receive. While some preparers submerge the nuts in water to rehydrate them, others spray them with water at regular intervals over the course of week to soften their sweet meat.

Finally the priests’ treats are ready to serve. Sold by the scoop at markets around Salerno, they have become a much-awaited sign of the Christmas season. The softened nuts can also be strung together in a format that Italians refer to as collana del prete, or the “priest’s necklace.” Whether hung around the tree or heaped on the table, this buttery sweet holiday treat is bound to bring the family together.