Preheat the oven to 350 degrees Fahrenheit.
Arrange hoagie rolls on a baking sheet.
In a medium saucepan, bring the beef broth to a simmer over medium-high heat.
Add the roast beef to the broth and warm for about 3 minutes, ensuring it's heated through.
Distribute the warmed roast beef evenly among the hoagie rolls.
Top each roll with 2 slices of provolone cheese.
Bake in the preheated oven until the cheese is melted, approximately 5 minutes.
Serve the sandwiches hot, with small bowls of the warm broth for dipping.