Preheat your oven to 350°F (175°C).
In a skillet, sauté the onions and garlic until translucent.
Add the beef broth and Worcestershire sauce, bringing to a simmer.
Season with salt and pepper to taste.
Add the sliced roast beef to the broth, allowing it to heat through.
Slice the hoagie rolls and place them on a baking sheet.
Layer the heated beef onto the rolls.
Top with a slice of provolone cheese.
Bake in the oven until the cheese is melted and bubbly, about 5-7 minutes.
Serve with a small bowl of au jus for dipping.