Assemble brine, whisk to blend/dissolve salt and sweetness. Place brisket in brine (use a large zip lock or a stock pan for this), let rest, refrigerated, 12-24 hours.
Preheat oven to 200º
Whisk together all ingredients in the spice rub.
Remove brisket from brine, let brine drain off by holding it over the sink. Place on a sheet tray lined with parchment paper and – if available – a low grate to lift the bottom of the brisket off the tray. Pour dry rub on brisket and rub all over. Shake remaining dry rub off the brisket and into the sink.
Place brisket in oven with a sheet of tinfoil as large as the baking tray resting on top.
Do not crimp the edges of the foil or seal the brisket, or even crumple it down around the brisket. Just rest the sheet on top of the meat.
Bake 8 hours (or overnight) until the brisket registers an internal temp of 180º.
Serve warm, in thick slices, with BBQ sauce or pan dripping gravy.