Philly Mushroom Sandwich

2 teaspoons Extra-virgin olive oil
1 Medium onion, sliced
4 mushrooms (Large portobello mushrooms, stems and gills removed (see Tip), sliced work great)
1 Large red bell pepper, thinly sliced
2 tablespoons Minced fresh oregano or 2 teaspoons dried
1/2 teaspoon Freshly ground pepper
1 tablespoon All-purpose flour
1/4 cup Vegetable broth or reduced-sodium chicken broth
1 tablespoon Reduced-sodium soy sauce
3 ounces Thinly sliced reduced-fat provolone cheese
4 Whole-wheat buns, split and toasted

Preparation

1. Heat oil in a large nonstick skillet over medium-high heat. Add onion and cook, stirring often, until soft and beginning to brown, 2 to 3 minutes. Add mushrooms, bell pepper, oregano and pepper and cook, stirring often, until the vegetables are wilted and soft, about 7 minutes.
2. Reduce heat to low; sprinkle the vegetables with flour and stir to coat. Stir in broth and soy sauce; bring to a simmer. Remove from the heat, lay cheese slices on top of the vegetables, cover and let stand until melted, 1 to 2 minutes.
3. Divide the mixture into 4 portions with a spatula, leaving the melted cheese layer on top. Scoop a portion onto each toasted bun and serve immediately.

Cook's Notes

Tip: If using portobello mushrooms--The dark gills found on the underside of a portobello are edible, but if you like you can scrape them off with a spoon.