2-3 lg. Spanish onions, sliced very thin
2 tbsp. butter, melted
1 tbsp. flour
2-3 cans Campbell's beef bouillon
Shredded Swiss cheese
Shredded Mozzarella cheese
Croutons

Cook sliced onions in melted butter over low heat until caramelized. Darker brown without burning improves the taste. Can take an hour or more. Sprinkle flour over onions, stir. Add beef bouillon and equal amount of water. Cook until it is to your taste, the longer the better.

Mix 2 cheeses. Put soup into ovenproof bowls. Add croutons. Top with cheese. Broil in oven until cheese is brown and bubbly.