INGREDIENTS
1
flank steak, trimmed
1/4 tsp
kosher salt
1/4 tsp
freshly ground black pepper
2 tsp
extra-virgin olive oil, divided
1 cup
thinly sliced onion
2
(5-inch) portobello mushroom caps, sliced
1 1/2 cups
thinly sliced green bell pepper
2 tsp
minced garlic
1/2 tsp
Worcestershire sauce
1/2 tsp
lower-sodium soy sauce
2 tsp
all-purpose flour
1/2 cup
1% low-fat milk
1 oz
provolone cheese (about 1/4 cup), torn into small pieces
2 tbsp
grated fresh Parmigiano-Reggiano cheese
1/4 tsp
dry mustard
4
hoagie rolls, toasted