Pat the beef roast dry with paper towels. Season all sides with salt and black pepper.

Heat the olive oil in a large skillet over medium-high heat. Sear the beef for 2–3 minutes per side, until browned. Transfer the roast to a slow cooker.

Add the sliced onions to the same skillet. Cook for 4–5 minutes until they begin to soften. Add the minced garlic and cook for another 30 seconds.

Pour a small amount of the beef broth into the skillet and scrape up any browned pieces from the bottom of the pan.

Add the onions, garlic, remaining beef broth, Worcestershire sauce, bay leaf, thyme, and rosemary to the slow cooker.

Cover and cook on LOW for 7–8 hours or on HIGH for 4–5 hours, until the beef is fork-tender. Similar French dip recipes use slow-cooked chuck or rump roast with beef broth, Worcestershire sauce, onions, and garlic to create tender beef and flavorful au jus.

Carefully remove the beef from the slow cooker and let it rest for 10–15 minutes.

Slice the beef thinly against the grain or shred it with two forks.

Strain the cooking liquid through a fine-mesh strainer into a saucepan or heatproof bowl. Discard the bay leaf and herbs. Reserve the onions for the sandwiches. The strained cooking liquid becomes the au jus for dipping.

Return the sliced or shredded beef to a small amount of the au jus to keep it warm and moist.

Preheat the oven to 375°F. Slice the rolls lengthwise and spread the cut sides with softened butter.

Place the rolls on a baking sheet and toast for 3–5 minutes, until lightly crisp.

Fill each roll with the warm beef and cooked onions. Top with provolone cheese.

Return the sandwiches to the oven and broil for 1–2 minutes, watching carefully, until the cheese melts.

Warm the remaining au jus in a saucepan and pour it into small dipping bowls.

Serve the French Dip Sandwiches immediately with warm au jus, horseradish sauce, or Dijon mustard.