- Cook onion in hot oil in large saucepan over medium heat 15 minutes, or until translucent and slightly browned, stirring frequently.
- Stir in teriyaki sauce. Add broth and pepper; bring to boil. Reduce heat; cover and simmer 10 minutes.
- Meanwhile, place 1 cheese slice over each toasted bread slice and broil until cheese melts and is golden brown.
- Divide soup evenly into 6 individual soup bowls. Place bread slices on top and serve immediately.