Place roast in a slow cooker. Pour French onion soup and beef consommé over the top.
Cover and cook on low for 8 hours or high for 4 hours.
Remove 3 cups of cooking liquid to a small saucepan. Bring to a boil, then reduce to a hard simmer until reduced by half, about 10 minutes.
Transfer beef to a pie plate and shred with a fork.
Place sandwich rolls in a 9x13-inch pan, fill with shredded beef and top with provolone. Cover with foil and bake at 350°F for 5 minutes or until cheese melts.
Serve immediately with the reduced cooking liquid on the side for dipping.
Notes
Slow cookers vary. If the meat does not shred easily, continue cooking until tender. Larger or doubled roasts require additional cooking time.