In a saucepan over medium heat, combine the beef broth, Worcestershire sauce, soy sauce (if using), garlic, onion powder, thyme, and rosemary.
Bring the mixture to a gentle boil, then reduce the heat and let it simmer for about 15-20 minutes. This allows the flavors to meld together.
After simmering, strain out the herbs and garlic for a smooth au jus. Season with salt and pepper to taste.
Keep the au jus warm over low heat while you prepare the beef and sandwiches.
Sear the BeefIn a large skillet, heat 1 tablespoon of butter over medium-high heat. Season the beef slices with a bit of salt and pepper.
Sear the beef slices in the skillet for 2-3 minutes on each side until they are golden brown but still tender.
Remove the beef from the skillet and set aside. Cover it with foil to keep it warm.
Toast the BreadPreheat your oven to 350°F (175°C). Spread a light layer of butter on the inside of each French roll or baguette.
Place the rolls on a baking sheet, buttered side up, and toast them in the oven for about 5 minutes or until they are golden and crisp.
Assemble the SandwichesArrange the seared beef slices on the bottom half of each toasted roll. Optionally, add a slice of cheese on top of the beef for extra flavor.
Place the sandwiches back in the oven for 2-3 minutes, just enough to melt the cheese.
Once the cheese is melted, top each sandwich with the other half of the roll.
Serve with Au JusLadle the warm au jus into small bowls or ramekins, one for each sandwich. Serve the sandwiches alongside the au jus for dipping. The experience of dipping each bite adds an extra layer of flavor!