Trim off excess fat from the brisket and add the 2 tsps of spice rub
Sear this on all sides
In a slow cooker add all the sauce ingredients and mix
Add the brisket and slow cook for 8 hours
After the cook time, store the meat and the sauce in the fridge overnight so the fat can solidify
The next day scrape off the fat and add the brisket to a roasting pan with the onions and cook in a 350 degree oven for 2 hrs
Add the sauce to a sauce pan and cook on low till it thickens
Taste and add sugar to balance the salt after the sauce thickens
Once the brisket is out of the oven, brush the bbq sauce on the surface
Serve with mashed potato and the caramelized onions