-Mix the salt, pepper, garlic powder, smoked paprika, and chili powder to make a rub.
-Rub the seasonings on both sides of the meat and allow it to sit for approximately 15 minutes.
-If necessary, cut the beef to fit into the slow cooker.
-Place a layer of onion rings on the bottom of the cooker and place the meat on top of the onions.
-Add the remaining onions on top of the beef along with the garlic cloves and bay leaves.
-In a medium-size bowl, whisk together the beer, sriracha, cocktail sauce, brown sugar, and 1 cup of water.
-Pour the beer mixture over the meat in the cooker.
-Cover and set the cooker to high and allow to cook for 4-5 hours (or you can do 7-8 hours on low if you need more time).
-Remove the brisket and the onions from the cooker, and cover to keep warm.
-Take 3-4 cups of the cooker sauce and add it to a medium saucepan.
-Over medium heat, bring the sauce up to a low simmer.
-In a small cup, mix together the cornstarch and the 2 tablespoons of water.
-Pour the cornstarch mixture into the hot sauce and stir to thicken.
-Slice the brisket against the grain and top with the onions and thickened sauce.
-Serve