In a small bowl mix together the salt, pepper, garlic powder, onion powder, and oregano. Rub the spice mixture all over the brisket on both sides, then place the brisket in a slow cooker, fat side up. Sprinkle the minced garlic over the brisket and top with the sliced onions, on and around it.
In a medium bowl whisk together the broth, soy sauce, and ketchup. Pour into slow cooker until the brisket is just covered.
Cook on LOW for 8 hours. Once done cooking, either keep in the slow cooker on WARM, or transfer to a wood board and cover with foil and let rest for 20 minutes.
Meanwhile, whisk together the arrowroot powder and water in a small bowl to create a slurry. Pour the slurry into the liquid in the slow cooker and whisk. The liquid will begin to thicken after 2-3 minutes.
Slice the meat against the grain and serve with sauce on top.
In a small bowl mix together the salt, pepper, garlic powder, onion powder, and oregano. Rub the spice mixture all over the brisket on both sides and set aside.
Turn on the sauté function and add a little oil to the bottom of the pot. Sear the brisket for 2-3 minutes on each side until lightly browned. If brisket is too big to fit, you can cut in half and sear in batches (this step is optional, but creates extra flavor).
Turn off sauté function and place the brisket in a Instant Pot, fat side up. Sprinkle the minced garlic over the brisket and top with the sliced onions, on and around it.
In a medium bowl whisk together the broth, soy sauce, and ketchup. Pour into pot until the brisket is just about covered.
Cook on high pressure for 90 minutes, then let naturally release for 15 minutes and release remaining pressure. Remove brisket and let sit on wood board to rest. Press sauté function again and bring the liquid to a boil.
Whisk together the arrowroot powder and water in a small bowl to create a slurry. Pour the slurry into the liquid in the Instant Pot and stir. The liquid will begin to thicken after 2-3 minutes.
Slice brisket against the grain, or shred with two forks before adding back to the sauce. Keep warm until ready to serve.