Sear brisket until brown on all sides, about 10 minutes. Remove brisket to a baking sheet. Add the onions and garlic to pan and cook over medium heat until the onions are golden, about 10 minutes. Return brisket to pan and add the beer and beef broth to pan. Cover with foil, place in oven and bake 4- 6 hours, until brisket is tender. Optional - Remove foil and bake an additional 30 minutes to reach a deep brown color.