3-day BBQ Brisket (oven or slowcooker)

Ingredients:
Brisket: 1 to 2 kg

Rub:
Sugar: 1 tbsp

Golden Syrup: 1 tsp
Paprika: 2 tsp
Garlic Salt: 1 tsp
Chili Powder: 1 tsp
Salt and pepper: approx. 1/2 tsp each

Sauce:
Apple cider vinegar
: 1/2 cup
Ketchup 1 1/2 cups
Sugar: 1/2 cups 
Golden Syrup: 1 tbsp 
Cayenne: 1 tsp
Pepper: 1 tsp
Chili powder: 1 tsp 
Soy sauce: 1 tbsp
Yellow onion: 1

Prep
Combine the ingredients for the rub, and apply them with your hands.
Let the brisket sit in the fridge for a day if you have time, or if you don't have time, at least 30 minutes.
Preheat the oven to 225ºF/107ºC
Cook the sauce in a saucepan until it thickens into a syrup (about 15 minutes) and then coat the meat.

Cooking with an oven
Add the brisket to a cooking tray and cover with sauce. Add 1-2 cups of water depending upon the depth of the tray and the viscosity of the sauce, and the and let it sit for 20 minutes

Cover the tray and put it in the oven for 9 to 12 hours, checking occasionally and adding water as necessary.

Once it is cooked in either the oven or slowcooker (see below), set in in the fridge for 12-24 hours, and reheat before the meal. 

Cooking with a slowcooker
Add the sauce and brisket into the slowcooker on high for 4 1/2 to 5 hours, or low for 10-12 hours