1
Set your crockpot to high and add the onions, butter, Worcestershire sauce, vinegar, garlic, brown sugar, salt, and pepper. Cook for 60 minutes until onions begin to brown and caramelize, stirring occasionally.
4
To serve with bread and cheese, slice a small piece of french bread (many people toast it first) and place on top of the soup. Cover with one slice of Swiss cheese and broil for 3 minutes.