Portobello "Philly Cheese Steak" Sandwich

source: Eating Well

• 
  2 teaspoons extra-virgin olive oil
  1 medium onion, sliced
  4 large portobello mushrooms, stems and gills removed (see Tip), sliced
  1 large red bell pepper, thinly sliced
  2 tablespoons minced fresh oregano, or 2 teaspoons dried
  ½ teaspoon freshly ground pepper
  1 tablespoon all-purpose flour
  ¼ cup vegetable broth
  1 tablespoon reduced-sodium soy sauce
  3 ounces thinly sliced reduced-fat provolone cheese
  4 whole-wheat buns, split and toasted

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.
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.
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.

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

source: Eating Well

Serving size: 1 bun and ¾ cup vegetable mixture
Per serving: 258 calories; 8 g fat(3 g sat); 6 g fiber; 35 g carbohydrates; 12 g protein; 64 mcg folate; 12 mg cholesterol; 8 g sugars; 3 g added sugars; 1,439 IU vitamin A; 57 mg vitamin C; 234 mg calcium; 2 mg iron; 537 mg sodium; 708 mg potassium
Nutrition Bonus: Vitamin C (95% daily value), Vitamin A (29% dv), Calcium (23% dv)