SEAR: Season the beef generously with a bit of salt and pepper. Add 1 tablespoon of butter to a cast iron skillet over medium-high heat. Sear the meat on all sides, about 8 minutes total. Place the roast in the slow cooker. Add the remaining tablespoon of butter to skillet and the sliced onions. Cook the onions for 5-7 minutes or until they start to soften.

SLOW COOKER: Add the onions to the slow cooker along with the remaining slow cooker ingredients, cover and let cook on low for 6-8 hours.The liquid may not cover the roast entirely, and that's okay. Sometime during those 6-8 hours, just give it a quick flip. You can also cook it on high but I find the meat doesn’t get as tender as it does when cooked low and slow. When the beef is cooked, remove from the broth to a cutting board and shred or slice the meat against the grain (this makes it even more tender). Add the beef back into the slow cooker for just a few minutes so it soaks up some of the juices (with the slow cooker off).

SANDWICHES: Position a rack near the center of the oven and preheat to 400ºF. Peel back the hoagie rolls. Pile on the meat, top with sliced cheese. Cover the rolls and bake until the cheese melts (about 6-10 minutes). While the sandwiches are baking, remove any remaining meat to air-tight containers and strain the cooking liquid through a fine mesh strainer. Serve the au jus (cooking liquid) with the sandwiches! Any leftover au jus should be stored in a separate container from the meat so the meat doesn’t fall apart.