Directions

1. Place a large frying pan over medium-high heat and add the oil.
2. Once the oil is hot, add the onions and sauté for 3 minutes, and then stir in the mushrooms, bell pepper, oregano and pepper, and continue to sauté for 7 additional minutes.
3. Turn the heat down to low and sprinkle the flour over the vegetables. Pour in the broth and bring the mixture to a simmer, stirring frequently. Cook for 1 minute and then remove from heat.
4. Spoon the mixture onto each toasted bun and top with a slice of cheese. Serve immediately.