Liberally salt and pepper the brisket
Whisk together the beef broth, liquid smoke, worcestershire sauce, garlic powder, and onion powder for the marinade
Add the marinade and the brisket to a large resealable plastic bag, squeeze out excess air, and seal the bag
Refrigerate for 24 hours, turning the bag occasionally so that the brisket is evenly marinated
Preheat the oven to 275 degrees
In a large baking dish, pour in the beer and add the garlic and onion
Remove the brisket from the marinade, discard the marinade, and add the brisket to the baking dish
Cover with aluminum foil and bake 6 hours
Let the brisket rest 15 minutes before slicing
Cut 1 cup of brisket into small pieces
Refrigerate left over brisket in an air tight container for 1 week