Make the burgers: In a mixing bowl combine the ground beef, beer, garlic powder, onion powder, pepper and salt. Mix well without over working the meat and form into 4 burger patties. Gently make an impression in the center of each patty. This will help keep them from shrinking. Grill to desired doneness.
Before removing from the grill top each burger with onions and a slice of Swiss cheese. Allow cheese to melt before removing from the grill. Place on burger buns and dress as desired.
Make the onions: Melt butter in a skillet over medium heat. Add onions and cook about 10 minutes until softened, stirring occasionally. Add broth, beer, brown sugar and seasonings, stirring occasionally. Cook 10 - 15 minutes until onions are caramelized and liquid is reduced. Set aside.