Be sure to use a fresh beef brisket instead of a corned beef brisket. A "corned" brisket is a fresh brisket that has been cured in seasoned brine, which would overpower the delicate flavor of the cranberry gravy. If a fresh brisket isn't available, use the same cut of beef roast that you use for your favorite pot roast.
We like the appearance of the whole berry cranberry sauce, but you can use a can of jellied cranberries if you like. Cranberries are native to North America. Pilgrims noticed that cranes flew in great flocks to the cranberry bogs and feasted on the sour red berries. Thus the berries got the name "craneberries," which later became "cranberries."