>>7006764There are two parts to a brisket: point and flat.
Sometimes, the two parts are separated before cooking, and the point (the fattier, larger part) takes longer to finish. So the term "burnt" just comes from the longer time.
At our place, we basically just cook the brisket whole, then use it for service. If there's any of the point left over, we'll cube it and smoke the cubes the next day (we also add additional rub.)
The result is a more flavorful and much more well-done piece of brisket that's still tender (and has more crust on the outside.)
This really can't be done well with the flat - the lack of fat means it just turns into chewy, leathery garbage.