1. Preheat oven to 325°F. Cook bacon in Dutch oven over medium heat until crisp. Remove bacon to paper towels. Place brisket, fat side down, into hot bacon fat. Brown on all sides. Remove to platter; set aside.
2. Pour off all but 2 tablespoons of fat. Add onions; cook and stir 3 to 4 minutes over medium-high heat until soft.
3. Add beer to Dutch oven. Bring to a boil over medium-high heat, stirring frequently and scraping up any brown bits from bottom of pan. Add brisket and broth; bring to a boil. Cover; roast 3-1/2 to 4 hours.
4. Remove brisket to cutting board and let rest 10 minutes. Trim off excess fat. Using slotted spoon, remove onions and set aside. Boil remaining liquid over high heat until reduced to about 2 cups.
5. Slice brisket and place on platter. Cover with onions and drizzle with sauce. Sprinkle with bacon and chopped parsley.
Tip
Serve remaining sauce in a gravy boat alongside brisket.