Trim excess fat from roast. Season roast with salt and pepper. Heat olive oil in a large nonstick skillet over medium high heat. Brown roast on all sides (about a minute each side).
Place roast in your slow cooker insert and add French onion soup, beef broth, root beer, soy sauce, garlic powder, bay leaves, thyme and oregano.
Cover and cook on low heat for 4 hours. Carefully remove roast, place on a cutting board and thinly slice across the grain. Place sliced meat back in slow cooker.
Cover and cook on low for an additional 1 to 2 hours (until desired tenderness). Remove and discard bay leaves.
Preheat your oven to 375 degrees F. Slice buns and place on a rimmed baking sheet (sliced side up). Place sliced beef on one half of each bun and top with 2 slices of provolone cheese. Bake until cheese is melted (about 3 minutes).
Serve with au jus from slow cooker.**