1. Peel and slice the onion. Peel and halve the garlic.
2. In the bottom of your slow cooker, loosely combine the broth, ketchup, and sugar.
3. Heat a large skillet over medium high heat and sauté onion and garlic in avocado oil until translucent.
4. Stir in spices and seasoning (paprika, salt, garlic and onion powders, black pepper, cayenne, oregano and thyme) and cook for 2 minutes. Set aside.
5. Place brisket in slow cooker and spread onion mixture over the top. Cover with the lid and cook it on low for 8-10 hours.
6. When brisket is cooked, but still hot with an internal temperature of 145F, use a spoon to scrape off any large fat deposits adhered to the top and bottom of the brisket.
7. Transfer the brisket and all of its sauce to a baking dish.
8. Chill entire dish in the fridge for several hours and up to one day; this resting time will significantly enhance the flavor and texture of the meat.
9. 1 hour before serving, preheat the oven to 300F. Remove the dish from the fridge and remove solidified fat to your preference.
10. Remove the meat to a cutting board and slice against the grain into half inch slices.
11. Use an immersion blender (or standing blender) to puree the sauce smooth.
12. Slide the sliced meat back into the sauce, cover, and cook for about 30 minutes until hot.