Preheat oven to 425 degrees F. Coat a large roasting pan with a few spritzes of olive oil; place brisket in pan, fat-side up.
Arrange cranberries, onions, garlic, carrots and cinnamon sticks around the outside edges of brisket. Sprinkle with basil.
Roast, uncovered, for 30 minutes.
Reduce oven temperature to 300 degrees F.
Spoon cranberry sauce over brisket. Seal pan tightly on all sides with foil.
Roast brisket for 3 hours or until fork- tender. Discard cinnamon sticks.
Carefully place about 1/2 of the veggies, cranberries, sauce and juices into a blender or food processor. Process on low speed or “pulse” until gravy has a slightly chunky consistency. (Puree in batches if needed.)
Pour gravy over brisket, combining with remaining vegetables and juices in pan.
Let cool; refrigerate, covered, for at least 8 hours or overnight. (Briskets are much easier to slice when cold.)
Slice the brisket thinly (against the grain); return to pan to soak in the gravy. Reheat brisket in a gentle oven (about 250 degrees F) until hot, about 25 minutes