Melt margarine in a 4 1/2 quart soup pot over medium heat. Stir in onion, Worcestershire sauce, and garlic. Pour in beer and increase heat to high. Boil mixture until alcohol is evaporated, about 3 minutes. Pour in broth and bring soup back to a boil. Lower heat to medium low and simmer.
Stir together cornstarch and water in a small bowl until smooth. Set aside.
Add half and half and cheese to soup; stir constantly until cheese melts. Stir in cornstarch mixture and continue stirring until soup is thick, about 2 minutes. Garnish with bacon bits.
Beer Cheese Soup · Dinner Match Lab | Dinner Match Lab