Brisket burnt ends?

Burnt ends are the best, love to make them.
At 165 IT I separate the point from the flat and cube it into about 2 - 3 inch cubes. I don't put any sauce on them but I do rub them down again with the same rub I used at the start of the smoke.
I place them back on the smoker and don't touch them again for about 2 1/2 hours to 3 hours. My wife always comments that they look like little charred pieces of meat but they are like candy, could eat them all day.

For the most part, the majority of people will separate the point and the flat once the flat has reached your desired doneness.  Typically, the point needs to cook for about 2 more hours than the flat due to higher co ncentration of internal fat in the point versus the flat.  Wrap the flat and place in a cooler for it's rest, then cube the point about 3/4" x 3/4", trimming any heavy layers of fat, throw them back in a foil pan with some au jus from the brisket cook, a bit more of your rub and some of your favorite Q sauce, enough to lightly coat each cube, the sauce can be spicy or sweet, we prefer sweet (Sweet Baby Rays).  Pop them back in the smoker or oven for a couple more hours, then enjoy.