(Taken from https://www.catholicculture.org/culture/liturgicalyear/activities/view.cfm?id=1029)
The St. Joseph Altar or St. Joseph Table is an old tradition from Sicily. Here is the explanation of how the tradition started.
The people of Sicily prayed. For too long there had been no rain to nourish the crops that sustained life for most of the island.
The dried out wheat stalks cracked beneath the feet of the poor farmers as they walked through their barren fields. Only a sea of dust and withered vines remained from what had once been row upon row of brightly colored fruits and vegetables.
And so the people prayed.
They pleaded to St. Joseph, their patron, for relief from the famine that gripped the island. At last the skies opened, sending down the life-giving water. The people rejoiced. Some time later, to show their gratitude, they prepared a table with a special assortment of foods they had harvested. After paying honor to St. Joseph, they distributed the food to the less fortunate.
The first St. Joseph Altar set up on the Island of Sicily was a small one, of course. But as time went on and the tradition took hold, the flamboyant nature and creative spirit of the Italians caused the altars to grow larger and more ornate.
Today, the artistic quality of the breads, cookies and pastries, which are baked in such shapes as chalices, staffs and pyramids, often rivals the exquisite flavor of the food offerings.
Though Sicilian immigrants introduced the custom to America, the celebration is not confined to any nationality. Rather, it has become a public event which its devoted participants embrace for a host of private and personal reasons. The feast is alternately a source of petition and thanksgiving.